Clinical UM Guideline

This document addresses the use of continuous glucose monitoring devices (CGMs, also referred to as continuous interstitial glucose monitoring devices) for the management of diabetes mellitus.

CGMs are devices that continuously measure glucose concentrations in the interstitial space of the skin, allowing for indirect blood glucose measurements and avoidance of some or all fingersticks to access capillary blood.  CGMs have been shown to assist in the management of some individuals with diabetes mellitus. Such devices come in a variety of configurations, including “flash” devices allowing on-demand measurements and devices that provide a continuous display of readings.

Note: This document does not address CGM devices approved for use without a prescription.

Note: For additional information regarding diabetes care, please see:

• CG-DME-50 Automated Insulin Delivery Systems
• CG-DME-51 External Insulin Pumps
• CG-SURG-79 Implantable Infusion Pumps

For a high-level overview of this document, please see “Summary for Members and Families” below. 

Medically Necessary:

I.  Personal Use of Non-Implanted Continuous Interstitial Glucose Monitoring Devices

Personal use of a non-implanted continuous interstitial glucose monitoring device is considered medically necessary for individuals who meet the following criteria:

1. Individual has been diagnosed with diabetes mellitus (any type); and
2. Insulin injections are required or an insulin pump is used for maintenance of blood sugar control; and
   1. Any of the following are present, despite ongoing management using self-monitoring and insulin administration regimens to optimize care:
      1. Inadequate glycemic control, demonstrated by HbA1c measurements above target; or
      2. Persistent fasting hyperglycemia; or
      3. Recurring episodes of hypoglycemia (blood glucose less than 54 mg/dL); or
      4. Hypoglycemia unawareness that puts the individual or others at risk; or
      5. In children and adolescents with type 1 diabetes who have achieved HbA1c levels below 7.0%, when treatment is intended to maintain target HbA1c levels and limit the risk of hypoglycemia.

Continued use of a non-implanted continuous interstitial glucose monitoring device for personal use is considered medically necessary when there is documentation that the device has resulted in clinical benefit (for example, improved or stabilized HbA1c control or fewer episodes of symptomatic hypoglycemia or hyperglycemia).

Replacement of a non-implanted continuous interstitial glucose monitoring device for personal use is considered medically necessary when the following criteria have been met:

1. The device is out of warranty; and
2. The device is malfunctioning; and
3. The device cannot be refurbished.

II.  Personal Use of Implanted Continuous Interstitial Glucose Monitoring Devices

Personal use of an implanted continuous interstitial glucose monitoring device is considered medically necessary when the criteria below have been met:

1. The individual is 18 years of age or older; and
2. The individual meets the medical necessity criteria above for a non-implanted continuous interstitial glucose monitoring device for personal use.

Continued use of an implanted continuous interstitial glucose monitoring device for personal use is considered medically necessary when there is documentation that the device has resulted in clinical benefit (for example, improved or stabilized HbA1c control or fewer episodes of symptomatic hypoglycemia or hyperglycemia).

Replacement of an implantable continuous interstitial glucose monitoring device for personal use is considered medically necessary in accordance with FDA-approved indications for use.

III.  Professional, Intermittent, Short-Term Continuous Interstitial Glucose Monitoring Devices

Use of a continuous interstitial glucose monitoring device for professional, intermittent, short-term use is considered medically necessary when all of the following criteria are met:

1. Individual meets medically necessary criteria for a non-implanted continuous interstitial glucose monitoring devices above; and
2. Monitoring and interpretation are under the supervision of a physician; and
3. The device is only used for a maximum of 14 consecutive days on an appropriate, periodic basis.

Not Medically Necessary:

Use of continuous interstitial glucose monitoring devices is considered not medically necessary when the criteria above have not been met.

Continued use of a continuous interstitial glucose monitoring device is considered not medically necessary when continued use criteria above have not been met.

Replacement of a continuous interstitial glucose monitoring device is considered not medically necessary when the replacement criteria above have not been met.

This document describes clinical studies and expert recommendations, and explains when treatment with continuous glucose monitors (CGMs) is appropriate. The following summary does not replace the medical necessity criteria or other information in this document. The summary may not contain all of the relevant criteria or information. This summary is not medical advice. Please check with your healthcare provider for any advice about your health.

Key Information: Continuous Glucose Monitoring (CGM) Devices

CGM devices are used by individuals with diabetes to monitor glucose (sugar) levels. These devices use a small sensor inserted under the skin to measure glucose levels in the fluid between the body’s cells. CGMs help track blood glucose levels without the need for frequent fingerstick blood tests. Many continuous glucose monitors provide ongoing glucose readings, alerts for high or low glucose levels, and data that can be used to improve diabetes management. Some CGMs display glucose readings all of the time, while others allow users to check glucose levels when needed. These tools can be used for daily personal use or short-term monitoring under the supervision of a healthcare provider.

CGM devices come in different types:

• Real-Time CGMs (rtCGMs): Show glucose levels continuously.
• Flash CGMs: Require users to scan the sensor to see their levels.
• Implantable CGMs: Placed under the skin by a healthcare provider and last for several months.

These devices can be used by people with type 1 or type 2 diabetes. CGMs may help avoid dangerously high or low blood glucose levels and may improve long-term health. Some devices have been approved for use without needing to calibrate them using a blood glucose meter. Calibration means ensuring that CGM readings match readings from traditional testing.

What the Studies Show

CGM devices have been studied most in individuals with type 1 diabetes. CGMs may improve blood glucose control, lower average blood glucose levels (measured by the A1c test), and reduce the time spent with low or high blood glucose. For type 1 diabetes, especially when individuals use the devices regularly, CGMs may help reach blood glucose targets with less risk for episodes of low blood glucose. Some studies also show benefits in children and teens, when CGMs are used consistently.

For individuals with type 2 diabetes, studies have shown mixed results. Some research shows improved blood glucose control, especially in individuals who use insulin. Others show benefits in short-term blood glucose levels or increased time spent in the target range. The evidence is less strong for individuals with type 2 diabetes who do not use insulin.

Flash CGMs have also shown benefits, including better blood glucose control and fewer episodes of low blood glucose, especially at night.

Implantable CGMs can last for months, making them a good option for some adults.

When is CGM Clinically Appropriate?

CGM devices may be appropriate in these situations:

• The person has type 1 diabetes or type 2 diabetes and
• Uses insulin or uses an insulin pump and
• One of the following is seen despite regular blood glucose checks and use of insulin:
  • Poor blood glucose control (high A1c)
  • Ongoing high blood glucose in the morning
  • Frequent low blood glucose (below 54 mg/dL)
  • Trouble noticing low blood glucose
  • A child or teen has type 1 diabetes and A1c under 7% and treatment aims to maintain control and avoid lows

Continued CGM use is appropriate if the device shows benefit, such as better or stable hemoglobin A1c, a measure of long term glucose control, or fewer episodes of low/high blood glucose.

Replacement may be appropriate when:

• The device is no longer under warranty and
• It is not working properly and
• It cannot be fixed.

When is CGM Not Clinically Appropriate?

The following are not considered clinically appropriate:

• Using a CGM device if the use is not clinically appropriate as referenced above.
• Continued use if no health benefit is seen
• Replacing a CGM if it still works or is under warranty

(Return to Description)

The following codes for treatments and procedures applicable to this guideline are included below for informational purposes. Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy. Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.

When services may be Medically Necessary when criteria are met:

When services are Not Medically Necessary:
For the procedure codes listed above when criteria are not met or for all other diagnoses not listed; or when the code describes a procedure, device or situation designated in the Clinical Indications section as not medically necessary.

Summary

Diabetes mellitus is a chronic metabolic disorder affecting millions of Americans and is characterized by impaired insulin production (type 1 diabetes, T1DM) or insulin resistance and relative insulin deficiency (type 2 diabetes, T2DM). Effective management requires maintaining blood glucose levels within a target range (generally 70-180 mg/dL) to reduce the risk of complications associated with hyperglycemia (including cardiovascular, renal, neurologic, and retinal injury) and hypoglycemia (including confusion, seizures, loss of consciousness, and increased mortality risk). Long-term glycemic control is commonly assessed using hemoglobin A1c (HbA1c), with a general target of 7% or lower for many nonpregnant adults, though goals are individualized based on age, comorbidities, and risk of hypoglycemia.

Continuous glucose monitoring (CGM) devices measure glucose concentrations in interstitial fluid and provide either real-time or intermittently scanned glucose data. These devices offer trend information, alerts for high and low glucose levels, and metrics such as time in range (TIR), time above range (TAR), and time below range (TBR). CGM systems may be used for personal long-term management or for short-term professional (diagnostic) monitoring under clinician supervision. Implantable systems are also available for use in adults.

A substantial body of randomized controlled trials and meta-analyses supports the use of CGM in individuals with T1DM and in those with T2DM treated with insulin. In these populations. CGM use by these individuals is associated with modest but clinically meaningful reductions in HbA1c, increased time in target glucose range, reduced time in hypoglycemia (particularly <54 mg/dL), and decreased glycemic variability. Benefits are most consistently demonstrated when devices are used regularly and in conjunction with structured diabetes management. Evidence also supports the use of predictive alert features to reduce hypoglycemic exposure in individuals at high risk.

In insulin-treated T2DM, CGM has demonstrated improvements in glycemic metrics and HbA1c compared with self-monitoring of blood glucose (SMBG), particularly in those with suboptimal control at baseline. In contrast, data for individuals with T2DM not treated with insulin are more limited, with mixed results and concerns regarding durability, adherence, and the relative contribution of concurrent education interventions.

Professional medical societies, including the American Diabetes Association (ADA), American Association of Clinical Endocrinology (AACE), and the Endocrine Society, recommend CGM for individuals with T1DM and for those with insulin-treated T2DM, especially when glycemic targets are not met or when there is problematic hypoglycemia or hypoglycemia unawareness. These organizations emphasize individualized selection of device type, and incorporation of CGM data into treatment decision-making.

Implantable CGM systems have demonstrated acceptable accuracy and safety in adults and have received FDA approval for extended-duration use. Professional (short-term) CGM may be used periodically to evaluate glycemic patterns and guide therapy adjustments when continuous personal use is not feasible.

Overall, the available evidence supports CGM use in individuals with diabetes who require insulin therapy and who have inadequate glycemic control, recurrent hypoglycemia, hypoglycemia unawareness, or persistent hyperglycemia despite optimized self-monitoring and treatment. Continued use is appropriate when objective clinical benefit is demonstrated. Use outside these populations, including nonprescription or unsupervised use, has not been shown to consistently improve clinically meaningful outcomes.

Discussion

According to the American Diabetes Association (ADA, 2026), diabetes is one of the most common chronic diseases in the United States (U.S.), with approximately 37 million Americans with diagnosed disease. Another 8.5 million are believed to have undiagnosed disease. Diabetes mellitus, the fourth leading cause of death in the U.S., is a chronic condition, marked by impaired metabolism of carbohydrate, protein and fat. The underlying problem in diabetes is in the production or utilization of insulin, a hormone secreted by the pancreas that controls the level of blood sugar by regulating the transfer of glucose from the blood into the cells. Poorly controlled diabetes mellitus can cause cardiovascular disease, retinal damage that could lead to blindness, damage to the peripheral nerves, and injury to the kidneys. Management of diabetes mellitus involves normalizing blood sugar levels without causing potentially dangerous hypoglycemia.

Type 1 diabetes (T1DM) can occur at any age, but is most commonly diagnosed from infancy to late 30s. In type 1 the pancreas produces little to no insulin, and the body’s immune system destroys the insulin-producing cells in the pancreas. Following diagnosis of T1DM, some individuals experience a temporary ‘honeymoon phase,’ during which residual insulin-producing cells continue to function and insulin requirements may decrease. This phase is transient and ends as autoimmune destruction of these cells progresses.

Type 2 diabetes (T2DM) typically develops after age 40, but has recently begun to appear more frequently in children. In T2DM, the pancreas still produces insulin, but the body does not produce enough or is not able to use it effectively.

Adequate glycemic control is critical for directing therapy in individuals with diabetes. Ideal blood sugar concentration ranges between 70 mg/dL to 180 mg/dL. Hyperglycemia, defined as blood glucose concentrations above 200 mg/dL 1 to 2 hours following a meal, is associated with headaches, thirst, fatigue, blurred vision, hunger, difficulty concentrating, and coma. Long-term exposure to hyperglycemia has been associated with organ damage (including loss of function of the kidney, liver, heart, and eyes), peripheral nerve damage, and high blood pressure. Hypoglycemia is defined as an episode of an abnormally low plasma glucose concentration (with or without symptoms) that exposes the individual to harm. A blood glucose concentration between 54 mg/dL and 69 mg/dL, considered mild hypoglycemia, may include hunger or nausea, elevated heart rate, fatigue, difficulty concentrating, and tingling of the oral area. Serious hypoglycemia, defined as a blood glucose concentration < 54 mg/dL, has been associated with confusion, loss of coordination, blurry vision, loss of consciousness, and seizures. As noted by the Endocrine Society (2023), blood glucose concentrations < 54 mg/dL is associated with increased risk for cognitive dysfunction and mortality. Individuals with persistent fasting hyperglycemia, hypoglycemia unawareness that puts the individual or others at risk, or recurrent episodes of serious hypoglycemia (< 54 mg/dL) may benefit from use of continuous interstitial glucose monitoring devices and automated insulin delivery devices if ongoing management using self-monitoring and insulin administration regimens to optimize care has not resulted in adequate glycemic control.

For individuals with diabetes, the gold standard clinical indicator of adequate blood sugar control is the measurement of glycosylated hemoglobin, also known as hemoglobin A1c, or HbA1c. Measurement of HbA1c provides information regarding the concentration of a specific type of modified hemoglobin in the blood that is directly associated with blood sugar metabolism and is used to ascertain the level of blood glucose control over the previous 3 to 4 months before testing. Individuals with diabetes should have a “target” HbA1c measurement value that will demonstrate treatment adherence as well as attainment of treatment goals.

The ADA (2026) states that an appropriate target for HbA1c concentrations for many nonpregnant adults with diabetes is 7% or lower. They also state that more stringent A1c goals (such as < 6.5% [< 48 mmol/mol]) may be appropriate “for selected individuals if they can be achieved without significant hypoglycemia, excessive weight gain, negative impacts on well-being, or undue burden of care or in those who have nonglycemic factors that decrease A1C (for example, lower erythrocyte life span).” They also add, “Lower goals may also be appropriate during the honeymoon phase.” For children with T2DM and a low risk of hypoglycemia, they state that an A1c goal of 6.5% (< 48 mmol/mol) should be considered. For those with a higher risk of hypoglycemia A1c goals should be individualized. Similarly, a goal of 6.5% (< 48 mmol/mol) is ideal in pregnant individuals when safe to achieve.

For some individuals with diabetes, the use of insulin injection therapy several times a day is insufficient to provide adequate control of blood sugar levels. An external insulin pump may be recommended in such cases. These devices are worn externally and are attached to a temporary subcutaneous insulin catheter placed into the skin of the abdomen. An insulin pump  uses a computer-controlled mechanism that administers the insulin at a set (basal) rate or provides bolus injections as needed. The pump typically has a syringe reservoir that has a 2- to 3-day insulin capacity. The purpose of the insulin pump is to provide an accurate, continuous, controlled delivery of insulin that can be regulated by the user to achieve intensive glucose control.

Whether an individual with diabetes uses injection therapy or an insulin pump, the individual needs to check glucose concentrations several times a day to make sure they are staying within normal blood glucose range. As with injection therapy, sometimes self-monitoring blood glucose management is also insufficient. Use of a continuous interstitial glucose monitoring (CGM) device may be warranted in such cases.

Continuous Interstitial Glucose Monitoring Devices

CGM devices continuously monitor glucose concentrations in the fluid interstitial fluid. Such devices are proposed as an adjunct to routine blood-based glucose measurements in individuals with trouble maintaining appropriate blood glucose levels despite frequent blood-based monitoring or those with frequent undetected hypoglycemic events. They are designed to provide real-time glucose measurements, which have been found to accurately reflect blood glucose levels.

CGM devices have special features such as low and high glucose concentration alarms and data storage for later analysis. The stored data has been shown to be useful in identifying ways to improve individual care by altering diet, exercise, medication types, and timing of insulin administration.

There are a wide variety of interstitial glucose monitoring devices available,  for professional or personal use. Devices for professional use are applied for a limited period and collect glucose data that are later reviewed retrospectively by a medical provider. There are several professional use devices on the market that allow for 6-, 7-, and 14-day monitoring intervals. Devices for personal use are worn for longer periods and provide real-time glucose readings directly to the individual.

The U.S Food and Drug Administration (FDA) has approved several devices for use in guiding treatment without the need for finger-stick blood glucose testing. These include the FreeStyle Libre Flash Glucose Monitoring System, Freestyle Libre 2, Freestyle Libre 3 (Abbott Diabetes Care Inc., Alameda, CA) as well as the Dexcom G6 and Dexcom G7 CGM systems (Dexcom, Inc. San Diego, CA). The Freestyle Libre Flash Glucose Monitoring System was the first CGM system approved by the FDA that did not require calibration by the user. The Freestyle Libre 2 and Freestyle Libre 3 devices which received FDA approval in November 2022 and April 2023, respectively, are comparable to the predicate Freestyle Libre Flash but have additional features. Similarly, the Dexcom G7 which received FDA approval in September 2022, has some additional features that are not found in the predicate Dexcom G6 CGM system.

As noted above, short-term use devices are intended to be used periodically, and are usually dispensed by the treating provider who then collects, analyzes and interprets the resultant data in a retrospective manner.

Personal CGM devices involve long-term use, are usually purchased by or for the individual for whom it has been prescribed, and are intended to be used continuously in real-time to help guide daily care. Periodic data downloading and analysis by the individuals or their provider may also occur and provide additional data to guide care.

The FDA approved the Eversense implantable continuous interstitial glucose monitoring system on June 21, 2018, for continually measuring glucose levels in adults 18 years and older with diabetes for up to 90 days. Additional approval for use up to 180 days was granted on September 30, 2020. This device has 3 components. A small sensor is implanted in the physician’s office under the skin of the upper arm. It is then removed when it expires and may be replaced with another sensor at a site on the other arm to allow continued monitoring. A removable transmitter applied on the skin interacts with the implanted sensor and sends information to a mobile phone application. The transmitter can provide discreet, on-body alerts for high or low blood glucose levels even when the smartphone is not nearby.

Meta-Analyses Data

The use of CGMs for the monitoring and treatment of T1DM has been the topic of many studies. These studies have investigated the use of these devices in several different populations, including children, individuals with difficulty with controlling their blood glucose levels, and pregnant women with diabetes. These studies have subsequently been subject to additional meta-analyses demonstrating significant benefits to (Benkhadra, 2017; Floyd, 2012; Gandhi, 2011; Langendam, 2012; Poolsup, 2013; Yeh, 2012).

The Gandhi study mentioned above included three RCTs that included participants with T2DM. The studied populations varied significantly, with some studies including individuals who required insulin therapy and others including those who did not. Their meta-analysis indicated statistically significant reductions in HbA1c with CGM when compared to self-monitoring of blood glucose (SMBG).

Likewise, the study by Poolsup previously described involved a meta-analysis of four trials including adults with T2DM. In their analysis, CGM appeared to result in improved HbA1c reductions compared to SMBG, with a pooled mean difference of -0.31% (p=0.04). These studies reported the use of different types of devices (for example, retrospective CGM vs. real-time CGM [rtCGM]) and significant variability in frequency of CGM use.

Representative RCTs Addressing CGM for Type 1 Diabetes

Since the publication of the seminal article by the Juvenile Diabetes Research Foundation (JDRF) Continuous Glucose Monitoring Study Group (Tamborlane, 2008), a large number of studies have provided evidence demonstrating significant benefits to individuals with T1DM when treated with CGM. When compared to the control group, the CGM group in this age group had significantly better results in regard to almost all measures of glycemic control, including: overall HbA1c change from baseline to 26 weeks (−0.71 to −0.35, p<0.001) improved, relative reduction in HbA1c of 10% or more (13% vs. 2%, p=0.003), number of participants achieving target HbA1c goals less than 7.0% with no severe hypoglycemic events (15% vs. 3%, p=0.006), and higher percentage of time within normal blood glucose range (p<0.001). The data for the 8- to14-year-old age group demonstrated a significantly greater relative reduction in HbA1c of 10% or more (p=0.04) and a higher percentage of participants achieving an HbA1c less than 7.0% (p=0.01). The 15- to 24-year-old group had no significant differences noted. The findings of this study suggest that CGM may provide benefit for adults over age 24 and, to a lesser degree, children, and adolescents under age 15. The authors note that the rate of sensor use between age groups may be related to the differences in clinical outcomes. The group with the least reported benefits, the 15-24 years-old, had only a 30% sensor use frequency. The group with the most benefit, those 25 years of age and older had the highest use of sensor frequency at 83%. The group with intermediate results, 8-14 years-old, had an intermediate frequency of use of 50%. The rate of parental supervision and support for CGM was greater for the 8-14 years age group than for the 15- to 24-year-old group, which may explain the higher rate of utilization and the significantly better results in younger children. The findings of this study suggest that significant benefits may be gained with CGM when a high level of monitoring adherence is achieved. It should be noted that this study population was composed of highly motivated individuals who measured their blood glucose levels 5 times a day or more and had a beginning HbA1c of 10% or less.

In an extension study of the study reported by Tamborlane, 214 of 219 (98%) control group participants were followed for an additional 6 months and asked to use CGM daily (JDRF, 2010). This included 80 participants who were at least 25 years old, 73 who were 15-24 years old, and 61 who were 8-14 years old. Among the 154 participants with baseline HbA1c at least 7%, there was a significant decrease in HbA1c at 6 months after CGM use in the older age group (mean change in HbA1c, -0.4% ± 0.5%, p=0.003). There was a significant treatment group difference favoring the CGM group in mean HbA1c at 26 weeks adjusted for baseline values. The authors concluded that CGM is beneficial for individuals with T1DM who have already achieved excellent control with HbA1c of less than 7.0% with SMBG.

Pediatric CGM use has been evaluated in several published studies. The results of the Diabetes Research in Children Network (DirecNet) Study Group RCT were published by Mauras in 2011. This study evaluated the use of CGM in the management of young children aged 4 to 10 years old with T1DM. In this study, 146 children were assigned to either CGM or usual care. At baseline, 30 children (42%) had an HbA1c of at least 8%. The primary outcome was reduction in HbA1c by at least 0.5% without the occurrence of severe hypoglycemia at 26 weeks. The authors reported that 19% in the CGM group and 28% in the usual care group (p=0.17) met this endpoint. Mean change in HbA1c, a secondary outcome, did not differ significantly between groups (-0.1 in each group, p=0.79).

Adult use of CGM has been evaluated in randomized controlled trials. Beck and colleagues (2017a) reported results from the DIAMOND randomized clinical trial, which included 158 adults with T1DM using multiple daily insulin injections and baseline HbA1c levels of 7.5% to 9.9%. Participants were randomized 2:1 to CGM (n=105) or usual care with SMBG (n=53). The primary outcome was change in centrally measured HbA1c from baseline to 24 weeks. Study completion was high, with 155 participants (98%) completing the trial.

CGM adherence was substantial, with a median use of 7 days per week at 4, 12, and 24 weeks; only 2 participants discontinued CGM prior to study completion. Mean HbA1c decreased by 1.1% at 12 weeks and 1.0% at 24 weeks in the CGM group, compared with reductions of 0.5% and 0.4%, respectively, in the control group. The adjusted between-group difference in mean HbA1c change at 24 weeks was −0.6% (95% CI, −0.8% to −0.3%; p<0.001). CGM use was also associated with improvements in several glycemic metrics. Median time spent with glucose levels <70 mg/dL was lower in the CGM group than in controls (43 vs. 80 minutes/day; p=0.002). At 24 weeks, participants in the CGM group had lower glucose variability (coefficient of variation 36% vs. 42%; p<0.001), greater time in range (70-180 mg/dL; 736 vs. 650 minutes/day; p=0.005), and less time spent in hyperglycemia (>180 mg/dL; 638 vs. 740 minutes/day; p=0.03). Rates of severe hypoglycemia were low and did not differ between groups (two events in each group). The authors concluded that, among adults with T1DM using multiple daily insulin injections, CGM use resulted in greater HbA1c reduction over 24 weeks compared with usual care, while noting that longer-term effectiveness and impacts on clinical outcomes require further study. Strengths of the study included its randomized controlled design, high study completion and CGM adherence rates, use of centrally measured HbA1c as the primary outcome, and a protocol that approximated usual clinical practice across both community and academic U.S. endocrinology sites. The study also evaluated multiple prespecified glycemic metrics beyond HbA1c, providing a more comprehensive assessment of glycemic control.

Limitations of the study included its relatively short duration (24 weeks), lack of blinding due to the nature of the intervention, and limited generalizability to individuals younger than 26 years, those with HbA1c levels outside 7.5%-9.9%, or those with T2DM. In addition, the trial was not powered to detect differences in severe hypoglycemia or long-term clinical outcomes. (Beck, 2017a)

Also in 2017, Lind and colleagues published the results of the GOLD trial. This RCT involved an open-label crossover randomized study design. The study involved 161 participants with T1DM and HbA1c (HbA1c) of greater than or equal to 7.5% who were treated with multiple daily insulin injections. All participants were assigned to receive their initial treatment with a CGM or SMBG for a period of 26 weeks followed by a washout period of 17 weeks and then another 26 weeks with the alternate treatment. Complete data for analysis was available for a total of 142 participants (88/2%). Mean HbA1c was 7.92% during the CGM phase and 8.35% during the control treatment phase (p<0.001). Overall mean use time during the CGM phase was 87.8% (range 86.5-91.9%). In participants using the CGM greater than 70% if the time, HbA1c was reduced by 0.46% compared to no reduction in those using CGM less than 70% of the time. Self-measurement of blood glucose (SMBG) was performed a mean of 2.75 times a day in the CGM group compared to 3.66 times per day in the control group. The mean percentage of time in a hypoglycemic state (< 70 mg/dL) was 2.97% in the CGM phase vs. 4.79% in the control phase. A second lower hypoglycemic threshold for blood glucose concentration of < 54 mg/dL also reported, with the mean percentage of time below that threshold reported as 0.79% for the GICM phase and 1.89% for the control phase. Severe hypoglycemic events were reported in 1 participant in the CGM phase and 5 participants in the control phase (p=ns). There were no significant differences between groups with regard to the rate of serious adverse events. The 19 participants without full data were younger, had significantly higher HbA1c, and had a history of hypoglycemic events. The authors made similar conclusions those of the DIAMOND study:

Among patients with inadequately controlled type 1 diabetes treated with multiple daily insulin injections, the use of continuous glucose monitoring compared with conventional treatment for 26 weeks resulted in lower HbA1c. Further research is needed to assess clinical outcomes and longer-term adverse effects.

The results from the DIAMOND and GOLD trials support use of CGM in individuals with T1DM. However, it should be noted that the benefits were modest with mean HbA1c reductions between 0.4 and 0.6% and no significant difference between CGM and SMBG with regard to the incidence of severe hypoglycemic events. Additionally, these study results involved highly motivated and monitored participants under the care of endocrinologists in the framework of a clinical trial.

Battelino (2017) reported results of an unblinded, randomized, parallel, controlled trial involving children 8 to 18 years of age with T1DM who were treated with insulin pump therapy. Participants were assigned in a 1:1 fashion to treatment with the Medtronic 640G system with the predictive low glucose management (PLGM) either on (n=47) or off (n=49). The trial’s duration was 2 weeks. A significant difference between groups was noted with regard to the number of hypoglycemic events (glucose concentrations < 65 mg/dL; ≥ 20 minutes long) with the PLGM ON group experiencing 4.4 episodes vs. 7.4 for the PLGM OFF group (p=0.008). Similar findings were reported when the data were stratified by day (2.9 vs. 4.6, respectively, p=0.022) and night (1.5 vs. 2.8, respectively, p=0.025). However, the number of hypoglycemic events below 50 mg/dL was not significantly different. The time spent below 65 mg/dL, 60 mg/dL, and 50 mg/dL was less in the PLGM ON group (p=0.0106, p=0.089, and p=0.0203, respectively). The time spent above 140 mg/dL was significantly higher in the PLGM ON group (p=0.0165), but time spent above 180 mg/dL and 250 mg/dL was not (p-value not provided). The time spent within range, 70-140 mg/dL was significantly shorter in the PLGM ON group (p=0.0387), but time spent within the 70-180 mg/dL range was not. Mean and median sensor glucose measurements, sensor glucose measurements at 7:00 AM, mean and median blood glucose measurements, blood glucose measurements at 7:00 AM, and morning ketones were not significantly different between groups. No device-related serious adverse events were reported. However, the device was replaced on three occasions, and multiple sensor-related problem were reported, mostly due to lost connectivity.

Abraham (2018) described an RCT involving children and adolescents aged 8 to 20 years old with T1DM assigned to treatment with either standard sensor-augmented therapy or the MiniMed 640G system with predictive low glucose suspend (PLGS) feature. The low glucose threshold was set for 61 mg/mL for the duration of the study. Participants were selected on the basis of having at least one hypoglycemic event (serum glucose < 3.5 mmol/L) or three episodes of being at risk of hypoglycemia (4.4 mmol/L) during a 2-week assessment period. All participants were required to use their assigned device at least 80% of the time and followed for 6 months following randomization. At the end of the study, 18 participants (21%) in the low threshold group were lost to follow-up and 6 participants (7%) in the 640G group were lost to follow-up. The intent-to-treat population included 154 participants, 74 in the sensor-augmented therapy group and 80 in the 640G group. Both groups demonstrated significant reductions in time spent in hypoglycemia:

Primary and Secondary Outcomes

No significant changes in HbA1c were noted in either group. The authors concluded that use of the 640G device with PLGS d feature reduced hypoglycemia without deterioration in glycemic control.

In 2018, Little and colleagues reported 24-month follow-up results following completion of the HypoCOMPaSS study. This was a 2 x 2 RCT comparing the following treatment methods: 1) Multiple Daily Injection therapy (MDI) with SMBG, 2) MDI with SMBG and rtCGM, 3) continuous insulin infusion with SMBG, and 4) continuous insulin infusion with SMBG and rtCGM. Participants all had T1DM and were between 18 and 74 years old. The intervention period consisted of 24 weeks during which participants were treated per assignment. This was followed by reversion to routine care with additional data collection and visits at 12, 18 and 24 months. During the follow-up period, participants were given the option to change their insulin delivery method and the CGM group was allowed continued use of the device while the SMBG group continued their self-monitoring. A total of 96 participants were randomized and 76 (79%) completed the 24-month study period. The MDI group contained 50 participants, with 39 (78%) completing the study period. Only 26% were still using this treatment method at end of the study. The insulin pump group began with 48 participants and 39 (81%) of them completed the study. A total of 68% were still using their pump at the end of the study. The CGM group involved 48 participants, with 37 (77%) completing the study, and 30% were still using the devices at the end of the study. The SMBG group began with 48 participants and 39 (81%) were retained at 24 months. All groups improved their hypoglycemic awareness with no significant differences were noted between the daily injection and pump groups with regard to hypoglycemia awareness over the 24-month study period. Likewise, no differences were reported between the SMBG group and the CGM group with regard to severe hypoglycemia or any secondary outcomes. Only 30% of CGM participants continued to use their devices for the full 24 months. In the overall population, there was improvement in hypoglycemia awareness, sustained throughout the study period (Gold score 5.1 vs. 3.7, p<0.0001). Similar results were reported for the severe hypoglycemia rate (8.9 episodes/person-year vs. 0.4, (p<0.0001) and HbA1c (8.2 vs. 7.7; p=0.003). The findings suggest that structured hypoglycemia-focused education with ongoing specialist support may be the principal driver of sustained benefit, regardless of insulin delivery or glucose monitoring modality.

Overall, the available RCT evidence addressing the use of CGM devices in individuals with T1DM is mixed but skewed to beneficial outcomes with the use of CGM devices. Data from meta-analyses supports this conclusion and indicates that the use of CGM results in improved glycemic control for adults with T1DM and for children with T1DM who used rtCGM devices.

Implantable Interstitial Glucose Monitors

Well-designed trials have demonstrated the accuracy of implantable CGMs when compared to both blood glucose measurements and non-implantable CGMs (Aronson, 2019; Boscari, 2021a and 2021b; Christiansen, 2018 and 2019; Jafri, 2020; Sanchez, 2019). Additional studies have demonstrated significant impact of the Eversense device on HbA1c concentrations and the effectiveness of alerts for hypoglycemia (Irace , 2020; Kropff, 2017; Tweden, 2020). Adverse event rates and sensor durability have also been shown to be within acceptable ranges (Deiss, 2019). A study by Renard (2021) demonstrated a significant decrease in time below range (< 55 mg/dL) as a result of Eversense use when compared to self-monitoring or non-implantable CGM use.

The results of these trials demonstrate reasonable accuracy relative to laboratory blood glucose measures. Additionally, the available data demonstrate acceptable long-term performance out to 180 days for the Eversense device. Use of this device has been accepted as equivalent to non-implantable devices in the most recent version of the ADA Standards of Care in Diabetes (2026).

rtCGM use in Individuals with Type 2 Diabetes

rtCGM devices utilize an interstitial glucose sensor device attached to the skin and linked to a monitoring device. The sensor constantly provides up-to-date glucose concentration data that the treated individual or their caregiver can use to guide treatment. Such devices also store data for analysis at a later date to evaluate trends. Several studies have demonstrated significant benefit from these types of devices (Beck 2017b; Blackberry, 2014 and 2016; Sierra, 2017; Yoo, 2008).

Furler (2020) published the results of an open-label RCT involving 299 participants with T2DM assigned to care with a flash CGM set to professional mode (n=149) or to standard care (n=150). Participants in the professional CGM group could not view the CGM data and were asked to wear the device for 5-14 days every 3 months over a 12-month period to capture data. Data were downloaded by each participant’s healthcare professional and discussed with the participant at the end of each recording period. Control participants wore the professional CGM device at baseline and 12 months only and the results were not discussed with them. There were no significant differences reported between groups with regard to the primary outcome measure, mean HbA1c at 12 months (-0.3% vs. -0.5%, p=0.59). However, at 6 months there was a significant difference reported (8.1% vs. 8.6%, p=0.001). The mean percentage time in target range was significantly better in the CGM group (54.8% vs. 46.9%, p=0.0043). The authors reported this difference was more pronounced between 6 a.m. and midnight, with the CGM group having a 9.2% higher mean percent time within target range (p=0.0021). No differences between groups was reported for this measure for midnight to 6 a.m. (p=0.06). From baseline to 9 months CGM use fell to 78%. Mean between-group difference in HbA1c results did not change when device non-users were removed from the analysis. No significant changes in median number of non-insulin drugs used, participants using insulin, or median total insulin dose were reported. The authors concluded that professional CGM use in individuals with T2DM did not improve HbA1c concentrations over 12 months. However, it did improve time in range (TIR) at 12 months and HbA1c at 6 months. While the results suggest a potential benefit of professional CGM use in individuals with T2DM, the authors note that the TIR outcome at 12 months findings were “exploratory and need to be interpreted with caution, particularly in the context of an open label trial in which the primary outcome was negative”.

Martens (2021) reported results for an RCT involving 175 participants with T2DM treated with basal insulin assigned to management with either CGM (n=116) or standard blood glucose monitoring (n=59). At 8 months follow-up, the mean HbA1c concentrations decreased significantly in the CGM group when compared to the blood monitoring group (9.1% to 8.0% in the CGM group vs. 9.0% to 8.4% in the blood monitoring group, p=0.02). Additionally, the mean percentage of time in the target glucose range (70 to 180 mg/dL) was 59% in the CGM group vs. 43% in the blood monitoring group (p<0.001). The mean percentage of time at greater than 250 mg/dL was also significantly improved in the CGM group (11% vs. 27%, respectively; p<0.001).

Lind (2024) reported the results of an unblinded RCT involving 76 adult participants with inadequately controlled T2DM who were assigned on a 1:1 basis to 12 month of treatment with either CGM with a Dexcom G6 (n=40) or SMBG (n=36). Major inclusion criteria were at least 1 year history of diabetes, HbA1c ≤ 7.5, and no prior CGM use. Additionally, all participants wore a blinded Dexcom G6 for 10 days duration at baseline, 6 months and after 12 months. Five participants were lost to follow-up, all in the standard care group, providing an overall completion rate of 93.4%. At 12 months, the results indicated a significant difference between groups with regard to TIR, with a 14.6% mean change in the CGM group compared to -0.6% (p=0.006) in the SMBG group. The between-group difference in change in HbA1c at 12 months was -0.9 (p=0.002), favoring the CGM group. The improvements in TIR were attributed to a greater reduction in time above range (TAR) in the CGM group, with a between-group difference in change of 15.5% at 12 months (p=0.006). The total daily dose of insulin likewise was significantly lower in the CGM group at 12 months (between-group difference -10.6 units, p=0.0256). The authors reported that, at 12 months, CGM group participants were more likely to have HbA1c ≤7.0% (33.3% vs. 16.7%, p=0.010) and HbA1c ≤7.5% (58 mmol/mol) (53.8% vs. 26.7%, p<0.0001). No significant differences between groups were found in regard to change in the number of glucose-lowering treatments used, nor were there any significant differences reported for hospitalizations or emergency room contacts. The authors concluded that the use of CGM for individuals with poorly controlled diabetes provided significant health outcome benefits.

The use of CGMs by individuals with T2DM has become an accepted practice and is currently recommended by the ADA (2023), and for all insulin-using individuals, regardless of diabetes type, by the American Association of Clinical Endocrinologists (AACE) and American College of Endocrinology (ACE, Grunberger, 2018).

Flash-CGM use in Individuals with Type 2 Diabetes

Flash CGM devices (for example, FreeStyle Libre Flash Glucose Monitoring System, Abbott Laboratories, Abbott Park, Ill) utilize an interstitial glucose sensor device attached to the skin for up to 14 days. This sensor takes measurements every 15 minutes, which may be accessed in real-time by triggering a separate reader/scanner unit wirelessly linked to the sensor. Such devices also store data for analysis at a later date to evaluate trends. Large, well conducted trials have demonstrated significant benefit from use of these types of devices (Al Hayek, 2017; Bolinder, 2016; Dunn, 2018; Ehrhardt, 2011; Haak, 2017a and 2017b; Saboo, 2018; Vigersky, 2012)

Most recently, in 2020 Yaron and colleagues reported the results of an unblinded RCT involving 101 participants with T2DM to 10 weeks of treatment with a flash glucose device (n=53) or SMBG (n=48). Flash group participants were asked to use the flash scanner every 8 hours, and the data was downloaded every 2-4 weeks. During inpatient visits, data from the flash device (Flash group) and the standard blood glucose monitor (Control Group) was used to counsel participants in self-care. In the ITT analysis, the mean (SD) change in HbA1c decreased -0.82% in the Flash group vs. -0.33 in the control group (p=0.005). HbA1c reduction, with adjustment for HbA1c values at baseline, was -0.85% in the Flash group vs. -0.32% in the control group (p<0.0001). The frequency of hypoglycemic episodes was not significantly different between the groups, and no severe hypoglycemic or serious adverse events were reported.

Overall, the data regarding the impact of flash CGM devices for individuals with T2DM demonstrates significant benefits with regard to decreased HbA1c concentrations and decreased overall and nocturnal time in the hypoglycemic range.

CGM use in Individuals with Type 2 Diabetes Not On An Intensive Insulin Regimen

The use of CGMs has been proposed for the management of glycemic control in individuals with T2DM not on an intensive insulin regimen. Such therapy involves the use of a CGM to help guide dietary and activity decisions to drive behavioral changes and self-management to improve outcomes. Such use has been referred to as “patient-driven lifestyle modification.”

Cox (2020) reported the results of a prospective, unblinded RCT involving 30 adult participants with non-insulin dependent T2DM assigned in a 1:2 ratio to standard care (n=10) or standard care plus rtCGM (n=20). The 2-month CGM group attended group sessions for 90 minutes on 4 occasions. One week occurred between sessions 1 and 2, and 3 weeks between sessions 2 to 3 and 3 to 4. Participants were given 5 G5 sensors to insert at each session and to be inserted 8 weeks before the 3-month follow-up assessment. Each session focused on different educational topics, including the influence of diet and exercise, and use of the device. The authors used “total treatment effect” (TTE) which combines HbA1c and medication effect scale (MES), as one of the primary outcomes. They reported that CGM significantly reduced HbA1c by 1.11% compared to the control group and significantly reduced MES 0.83 compared to the control group (no p-values provided). They reported a significant improvement in TTE in the CGM group compared to the control group by an “HbA1c equivalent of 1.94%” (p<0.001). The results indicated the CGM group increased in knowledge leading to a significant reduction in carbohydrate ingestion relative to the control group. However, the CGM group did not significantly differ from the control group in regard to physical activity level or glucose excursions (no p-values provided). Results for secondary outcomes indicated a significant improvement in the CGM group compared to the control group on World Health Organization (WHO)-Quality of Life (Psychological subscale), Diabetes Empowerment, Diabetes Distress Scale (Emotional and Regimen subscales), and the Glucose Monitor Satisfaction Survey (no p-values provided). No significant improvement in WHO-Quality of Life (Physiological subscale) was noted. The authors concluded that their CGM-supported education program “appears to be a safe, effective lifestyle intervention option for adults with suboptimally controlled T2D who do not take insulin.” However, the results of this trial cannot be solely attributed to the use of CGMs. The educational support provided to the CGM group but not the control group may have had a substantial impact on the measured outcomes.

Price (2021) conducted a prospective randomized, pilot trial involving 70 individuals with T2DM using non-insulin therapies and HbA1c values of 7.8-10.5%. Participants were randomized in a 2:1 fashion to receive either rtCGM with a Dexcom G6 (n=46) or SMBG (n=24). The rtCGM group used unblinded rtCGM for three sessions (week 0, 4, and 8). The control group used SMBG and wore blinded rtCGM at week 8. The CGM group were provided learning modules with each CGM wear period to facilitate understanding and use of their glucose data. Medication changes were not allowed in either group, unless required for safety. Phone visits with a study clinician were conducted at weeks 2, 6, and 10 in both groups to review the SMBG or rtCGM data, discuss what the participant learned from glucose data, what changes were made in response to the data, and what the study clinician observed. After week 12, participants were followed via usual care by their own clinician and returned for a follow-up visit at month 9 with study staff. At 12 weeks, both groups had significant improvements in mean and median change in HbA1c but there were no significant differences between groups (p=0.74). Furthermore, HbA1c reductions were not sustained at 9 months. The authors stated that time spent in hypoglycemia was negligible at run-in, precluding any meaningful conclusions about differences between groups. The CGM group experienced more than a 5% increase in TIR from baseline to week 8 (56.3% to 63.1%; no p-value provided). The authors stated this was primarily due to a reduction in hyperglycemia. Conversely, the SMBG group experienced a considerable decrease in TIR (68.4% to 55.1%; no p-value provided). No serious adverse events (SAEs) occurred in either group during the active wear period. The results of this exploratory trial appear to indicate some short-term benefit to episodic rtCGM for some non-insulin dependent individuals failing medical therapy. However, the authors noted that the small sample size “impacted the ability to draw statistically significant conclusions.”

In 2020, Bergenstal reported the results of a partially investigator-blinded RCT involving 114 individuals with uncontrolled T2DM (A1c ≥ 7.0%) treated with one of the following three therapies: 1) sulfonylurea (SU) ± metformin (SU group), 2) incretin (DPP4 inhibitor or GLP-1 agonist) ± metformin (incretin group), or 3) insulin ± metformin (insulin group). Participants were randomly assigned to treatment with either SMBG (n=55) or rtCGM device (n=59, DexCom SevenPlus CGM), and followed for 16 weeks, with endocrinology clinic visits once every 4 weeks. SMBG group participants were instructed to perform SMBG 4 times per day with a monitor that provides real-time blood glucose profiles of the preceding 3 days. The device was described as integrating experiential learning with clinical decision-making to guide treatment adjustments to achieve and maintain therapeutic goals. The CGM group was offered minimal training about how to use CGM data for making self-care adjustments. SMBG participants used a blinded CGM device 2 weeks prior to week 8 and 16 visits. The CGM group received a report during each clinic visit to assist with therapy changes. Participants using CGM had basic education on how to make dietary or medication adjustments based on CGM data. The primary outcome was glucose control based on HbA1c changes. The secondary outcome was change in the rate of hypoglycemia. Both groups demonstrated statistically significant HbA1c reductions at 16 weeks (-1.12% [p<0.001] in the CGM group; -0.82% [p<0.001] in the SMBG group), with no statistical differences between groups (p=0.11). Both groups also showed a statistically significant improvement at 16 weeks in AUC (area under the curve), percent of time in range, interquartile range (IQR), and rates of hyperglycemia (no p-values provided). While the CGM group showed improvement in rates of hypoglycemia, the changes were not statistically significant. The SMBG group demonstrated a statistically significant increase in hypoglycemia rates from baseline to 16 weeks (no p-values provided). There were no reported adverse events for this study. A pre-specified secondary outcome analysis, which the authors noted was not powered to demonstrate statistical significance, examined the percent of readings in hypoglycemic range by therapy type and testing group. They reported that, for all three therapy types, the CGM group experienced fewer hypoglycemic episodes in relation to the SMBG groups. They postulated that this result was driven primarily by the insulin and SU treatment groups. The authors concluded that either SMBG or CGM can lower A1c for individuals with T2D. However, the results of this study did not provide strong evidence of equivalency, as it was not powered or designed as a noninferiority trial.

Wada (2020) reported the results of an unblinded RCT involving 100 non-insulin-treated participants with T2DM and HbA1c ≥ 7.5% who were randomized to treatment with either intermittently scanned CGM (isCGM) (n=49, Free Style Libre) or SMBG (n=51). Participants in both groups received instruction on how to use each device and how to adjust their diet and lifestyle based on the blood glucose levels. The CGM group wore the device for 12 weeks. Participants in the SMBG group wore a blinded sensor (Free Style Libre Pro) for the last 2 weeks of the 12-week period. The primary outcome was the change in HbA1c levels. Forty-eight participants in the CGM group and 45 in the SMBG group completed the study. At 12 weeks HbA1c was significantly reduced from baseline values in both groups (CGM, -0.43%, p<0.001; SMBG, -0.30%, p=0.001). No significant between-group differences were reported (p=0.241). At 24 weeks, HbA1c was significantly decreased from baseline in the CGM group but not in the SMBG group (CGM, -0.46%, p<0.001; SMBG, -0.14%, p=0.124). A significant between-group difference was reported at this time point (p=0.022). Participants with sensor data recorded for < 5 days were excluded, leaving 41 participants in the CGM group and 35 in the SMBG group in the analysis. There were significant improvements in the CGM group compared with the SMBG group for the following parameters: mean glucose levels, standard deviation of glucose (p<0.001), blood glucose risk index (p=0.005), continuous overlapping net glycemic action (CONGA)-2 hour (p<0.001), mean amplitude of glycemic excursions (MAGE, p<0.001), mean of daily difference (MODD, p=0.006), time in sensor glucose 70-180 mg/dL (p<0.001), and time in hyperglycemia (p<0.001). There were no significant between-group differences with respect to the changes in glucose coefficient of variation (p<0.762) and the time in hypoglycemia (p<0.423). No significant between-group differences were observed in changes in antidiabetic drug utilization at 12 and 24 weeks. Eight participants reported 8 device-related adverse events, 7 in the CGM group and 1 on the SMBG group. All involved skin problems related to physical contact with the sensor. There were no reported serious adverse events. The authors noted that they did not record lifestyle changes or whether the use of CGM leads to lifestyle changes resulting in the changes reported. They theorized that lifestyle changes may explain the duration of HbA1c and glucose changes even after cessation of a CGM between 12 and 24 weeks. They also noted that the short duration of the trial does not allow understanding of the durability of the results reported.

Hayase (2023) conducted a post-hoc analysis the RCT previously reported by Wada (2020). The analysis investigated the factors that influenced CGM efficacy. They reported the scanning frequency by participants decreased gradually from a mean of 9.2 scans/day at week 1 to a mean of 6.4 scans/day at week 12. They also reported the percentage of time that the CGM was active, which was noted to have decreased from a mean of 97.1% at week 1 to a mean of 86.1% at 12 weeks. They reported a correlation between the changes in HbA1c at 12 weeks and the percentage of time that CGM was active (r= -0.39, p=0.009). They did not find any significant correlation between the mean scanning frequency and changes in HbA1c levels at 12 weeks (r= -0.17, p=0.276) or at 24 weeks (r= -0.06, p=0.679). Similarly, no correlation was reported between changes in HbA1c levels and the percentage of time that CGM was active at 24 weeks (r= -0.13, p=0.395). The median scanning frequency for the entire intervention period was 7.7 scans/day and the percentage of time that CGM was active was 87.5%. Additionally, they investigated the correlation between the reduction in HbA1c at 12 or 24 weeks and baseline parameters. An improvement in the Diabetes Treatment Satisfaction Questionnaire (DTSQ) score regarding “willingness to continue the current treatment” (Question 8) was associated with an improvement in HbA1c at 12 weeks (r=0.39, p=0.009). Also, the improvement in HbA1c at 24 weeks, 12 weeks, after the end of the CGM provision period, was significantly associated with the improved DTSQ scores regarding “flexibility” (r=0.36, p=0.014) and improved Question 8 scores (r=0.37, p=0.012). The authors concluded that glycemic control improved shortly after initiation of CGM use and that these improvements were associated with increased treatment satisfaction among non-insulin-treated individuals with T2DM. However, these findings are derived from a post-hoc analysis of a single, short-duration trial and are therefore exploratory in nature. The limitations of the underlying Wada (2020) study, including small sample size, short follow-up, unblinded design, and potential lifestyle confounding, apply to this analysis. In addition, the post-hoc methodology increases the risk of bias and limits the ability to draw causal inferences or generalize the findings. As such, the results should be interpreted cautiously and considered hypothesis-generating rather than confirmatory.

Choe (2022) published the results of a non-blinded RCT involving 126 participants with T2DM treated with anti-diabetes medication, including oral agents and basal insulin, but not prandial insulin. Participants were randomized to receive either standard treatment (n=63) or an intervention including education support with behavior modification and self-management with the use of isCGM FreeStyle Libre (n=63). The authors reported mean HbA1c levels were significantly improved in the intervention group vs. the control group (7.3 ± 0.6 in the CGM group vs. 7.8 ± 0.9% the control group at 12 weeks, p<0.001). Additionally, the proportion of participants achieving HbA1c < 7.0% was significantly higher in the CGM group (24.1% vs. 8.1%, p=0.016). Mean fasting glucose level was also lower in the CGM group than in the control group at 12 months (136 mg/dL vs. 154 mg/dL, p=0.017). No significant differences between groups were reported with regard to body weight, waist circumference, or lipid profiles.

Aronson (2023) reported the results of another RCT involving 116 participants with T2DM, HbA1c of 7.5% or higher, and at least one non-insulin anti-diabetes medication. Participants were assigned to diabetes self-management education (n=52) or to education with behavior modification and self-management with the use of isCGM (FreeStyle Libre) (n=53). Randomized treatment lasted for 16-weeks and was followed by another 16-week extension phase but the extension phase data are not provided in this report. The primary outcome was TIR, and the results at the last timepoint indicated that the percentage TIR was significantly better in the CGM vs. the control group (p<0.01). Percentage time in glycemic range and percentage time above range were significantly better in the CGM group compared to the control group (p=0.042 and p=0.037, respectively). No differences between groups were found with regard to time below range or mean glucose concentrations. Both groups had significant improvements in mean HbA1c. However, no between group comparisons were provided. No differences between groups were found for weight, waist circumference, or hypoglycemic events.

Moon (2023) conducted a prospective, unblinded RCT involving 61 participants with noninsulin-treated T2DM unable to be controlled with oral antidiabetic drugs. Participants were assigned to treatment with a single 1-week-long session of rtCGM (Medtronic Guardian Connect system, n=20), two 1-week-long sessions of rtCGM with a 3-month interval between sessions (n=21), or SMBG (n=20). All participants had a 6-day blinded CGM period prior to the start of the randomized trial period, the data from which was used to provide a pre-randomization education session. The primary outcome was the change in HbA1c at 6 months. All participants were advised to perform SMBG freely. After randomization, participants were not offered additional education other than instruction on device use. The study lasted 24 weeks, and 1 week prior to study completion all participants underwent blinded CGM use for up to 6 days. Thirteen participants (21%) did not complete the study, 5 in the SMBG group, 2 in the 1-week CGM group and 6 in the 2-week CGM group, leaving 48 participants included in the assessment. At 24 weeks, changes in HbA1c were 0.0 ± 1.1% in the SMBG group, -0.6 ± 1.0% in the single week CGM group and -0.6 ± 0.7% in the 2-week CGM group. Compared with the SMBG group, the 2-week CGM group achieved significant HbA1c reductions (adjusted difference, -0.68%, p=0.018). The change for the 1-week CGM group did not reach statistical significance (adjusted difference, -0.67%, p-0.082). No significant between-group differences were reported for TIR, time below range, or time above range. The median frequency of SMBG during the study period for all participants was 1.5 times per day. The participants who performed SMBG at least 1.5 times per day showed a significant HbA1c improvement at both 3 and 6 months (p=0.005 and p=0.18, respectively). In a subgroup analysis, most glycemic outcomes showed no statistical differences with regard to different oral antidiabetic drug groups. No significant between-group differences were reported for blood pressure, lipid variables, body weight at 6 months, fasting C-peptide level, fasting insulin level, homeostatic model assessment for insulin resistance (HOMA-IR), HOMA of ß-cell function (HOMA-ß), or quantitative insulin check index (QUICKI). Two adverse events were reported, one severe hypoglycemic event in the 1-week CGM group and one skin rash in the 2-week CGM group. The authors had calculated that a sample size of 16 participants for each group was needed to provide at least 80% power and a two-sided α of 0.05, which was achieved despite at 21% drop out rate. However, they note that the small number of participants in this study may have limited the power to detect differences between groups with regard to secondary outcome measures. The short follow-up period also did not allow understanding of long term outcomes.

Ferreira (2024) published a meta-analysis of RCTs involving the use of CGMs by individuals with T2DM who were not receiving insulin therapy. The analysis involved six studies discussed above that investigated the use of CGM compared to SMBG (Aronson, 2023; Bergenstal, 2022; Cox, 2020; Moon, 2023; Price, 2021, and Wada, 2020), with a total of 407 participants, 228 of whom received treatment with CGM and 179 who received SMBG. As detailed above, four of the studies involved the use of rtCGM and two involved the use of isCGM. A significant reduction was reported in HbA1c (p<0.01), glucose level (p=0.01), percentage of time with glucose level > 180 mg/dL (p<0.01), and time with glucose level < 54 mg/dL (p= 0.03) in the CGM group compared to the SMBG group. A significant increase in TIR (p<0.01) was reported in the CGM group compared to the SMBG group. No significant difference between groups was reported with regard to time with glucose level < 70 mg/dL (p=0.09). While the authors reported a significant decrease in the SD of glucose level in the CGM group compared to the SMBG group (p<0.01), no significant difference was detected in the coefficient of variation of glucose level between groups (p=0.26). In a subgroup analysis, both HbA1c (p<0.01) and time with glucose level < 70 mg/dL (p=0.01) were significantly better in the rtCGM group compared to SMBG group. However, no significant differences were reported between rtCGM and SMBG for TIR (p=0.07), time with glucose level > 180 mg/dL (p=0.15), and time with glucose level < 54 mg/dL (p=0.12). For the isCGM group, the HbA1c (p<0.01) and time with glucose level > 180 mg/dL (p<0.01) were both significantly lower compared to the SMBG group. Additionally, TIR (p<0.01) was significantly increased in the isCGM group when compared to SMBG. No significant differences were reported for time with glucose level < 70 mg/dL (p=0.43) and time with glucose level < 54 mg/dL (p=0.60). Another sub analysis was conducted regarding continuous and periodic (professional) use of CGM. The authors reported that, compared to the SMBG group, continuous use of CGM resulted decreases in HbA1c (p<0.01), time with glucose level < 70 mg/dL (p=0.04) and < 54 mg/dL (p=0.04), and in time with glucose level > 180 mg/dL (p<0.01). TIR in the continuous use group was similarly better for CGM than for SMBG (p<0.01). For periodic use, there was no significant difference when compared to SMBG for any measure. The authors stated that, based on the GRADE assessment, the quality of outcomes for HbA1c, TIR, and time in glucose level > 180 mg/dL were all of moderate quality. However, the outcomes for time with glucose level < 70 mg/dL and < 54 mg/dL, and overall glucose level was low-quality. Regarding risk of within-individual study bias, they reported that all studies were considered at low risk. However, some publication bias was reported with regard to outcomes related to time with glucose level < 70 mg/dL and < 54 mg/dL. It must be noted that the limitations and concerns regarding the included studies specified above also apply to this data, and as such, generalizability may be limited.

Shields (2024) published a trial assessing the use of CGMs in 182 participants with T2DM either not using insulin or those using basal but not bolus insulin. They reported favorable results in glycemic control at 3 months in the CGM group (n-911) compared to usual care group (n=91). However, the authors did not provide data or results stratified by participants who were receiving insulin therapy compared to those not receiving non-insulin therapy. As a result, these results are not useful in determining the value of CGMs by individuals with T2DM not undergoing insulin therapy.

The use of CGMs for non-insulin requiring individuals with T2DM continues to be studied and the clinical utility in this population remains uncertain.

Major Specialty Medical Society Recommendations

The ADA Standards of Medical Care in Diabetes-2026 has recommendations regarding the use of continuous glucose monitoring. These recommendations state:

6.1       Assess glycemic status by A1C A and/or continuous glucose monitoring (CGM) metrics such as time in range, time above range, and time below range. B Fructosamine or CGM can be used for glycemic monitoring when an alternative to A1C is required. B
6.3a      An A1C goal of 70% in people using CGM is appropriate for many nonpregnant adults without severe hypoglycemia or hypoglycemia affecting health or quality of life. A 
6.3b     A goal time in range of >70 in people using CGM is appropriate for many nonpregnant adults. B
6.3c      A goal percent time <70 mg/dL (<39 mmol/mol) of 4% (or <1% for older adults) and a goal percent time <54mg/dL (<3 mmol/L) of <1% are recommended in people using CGM to prevent hypoglycemia. Deintensify or modify therapy if these goals are not met. B
6.4       Lower A1C goals (e.g., <6.5% [48 mmol/mol]) may be appropriate for individuals with diabetes with good health and function and low treatment risks (e.g., hypoglycemia) and burdens (see Fig. 6.1). B
6.5       Less stringent glycemic goals may be appropriate for individuals with significant cognitive and/or functional limitations, frailty, or severe comorbidities or where the harms of treatment, including hypoglycemia, are greater than the benefits. B
6.14     Use of CGM is beneficial and recommended for individuals at high risk for hypoglycemia. A
7.1       Diabetes devices should be offered to people with diabetes. A
7.2       The type(s) and selection of devices should be individualized based on a person’s specific needs, circumstances, preferences, and skill level. In the setting of an individual whose diabetes is partially or wholly managed by someone else (e.g., a young child or a person with cognitive impairment or dexterity, psychosocial, and/or physical limitations), the caregiver’s skills and preferences are integral to the decision-making process. E
7.3a     When prescribing a continuous glucose monitoring (CGM) device, ensure that people with diabetes and caregivers are offered initial and ongoing training and education  as indicated by individual circumstances. Education should include utilization of data, including uploading or sharing data  to monitor and adjust therapy. C
7.5       People with diabetes who have been using CGM, continuous subcutaneous insulin infusion (CSII), and/or automated insulin delivery (AID) for diabetes management should have continued access across third-party payors, regardless of age or A1C levels. E
7.8       Consider early initiation, including at diagnosis, of CGM, CSII, and AID depending on a person’s or caregiver’s needs and preferences. C
7.15     Use of CGM is recommended at diabetes onset and anytime thereafter for children, adolescents and adults with diabetes who are on insulin therapy, A on noninsulin therapies that cause hypoglycemia, C and on any diabetes treatment where CGM helps in management. C The specific CGM device should be made based on the individual’s circumstances, preferences, and needs. E
7.16     In people with diabetes on insulin therapy, CGM devices should be used as close to daily as possible for maximal benefit. A People with diabetes should have uninterrupted access to their supplies to minimize gaps in CGM. A
7.17     During pregnancy for individuals with type I diabetes, CGM can help achieve glycemic goals (e.g., time in range and time above range) A and A1C goal B and may be beneficial for other types of diabetes in pregnancy. E See Section 15, “Management of Diabetes in Pregnancy,” for more detail regarding use of technology in pregnancy,
7.18     In circumstances when consistent use of CGM is not feasible, consider periodic use of personal or professional CGM to adjust medication and/or lifestyle. C
9.25     Use of continuous glucose monitoring (CGM) is recommended at diabetes onset and anytime thereafter for adults with diabetes who are on insulin therapy, A on noninsulin therapies that can cause hypoglycemia, B and on any diabetes treatment where CGM aids in management. B The choice of CGM device and method for use should be made based on the individual’s circumstances, preferences, and needs.
13.5     Recommend continuous glucose monitoring (CGM) for older adults with type 1 diabetes A and type 2 diabetes on insulin therapy B to improve glycemic outcomes, reduce hypoglycemia, and reduce treatment burden.
13.7a    Older adults with diabetes with few and stable coexisting chronic illnesses, and intact cognitive and functional status, should have lower glycemic goals (such as A1C <7.0-7.5% [<53-58 mmol/mol]) and/or time in range [TIR] 70-180 mg/dL [3.9-10.0 mmol/L] of ≥70% and time below range ≤70 mg/dL [≤3.9 mmol/L] of ≤4%) if CGM is used. C
13.7b   Older adults with diabetes and intermediate or complex health are clinically heterogeneous with variable life expectancy. Selection of glycemic goals should be individualized and should prioritize avoidance of hypoglycemia, with less stringent goals (such as A1C <8.0% [<64 mmol/mol] and/or TIR 70-180 mg/dL [3.9-10.0 mmol/L] of ≥50% and time below range <70 mg/dL [3.9 mmol/L] of <1% for those with significant cognitive limitations, frailty, severe comorbidities, and less favorable risk-t-benefit ration of diabetes medicine. C
14.16   Continuous glucose monitoring (CGM) should be offered for diabetes management at diagnosis or as soon as possible in children and adolescents with diabetes who are capable of using the device safely (either by themselves or with caregivers). A The choice of device should be made based on the individual’s and family’s circumstances, desires, and needs.
14.21   Less stringent A1C goals (such as <7.5% [<58 mmol/mol]) may be appropriate for children and adolescents with diabetes who cannot articulate symptoms of hypoglycemia; have hypoglycemia unawareness; cannot access advanced insulin delivery technology and/or CGM; cannot check blood glucose regularly; or have nonglycemic factors that increase A1C. B
14.22   Even less stringent A1C goals  may be appropriate for children and adolescents with a history of severe hypoglycemia, limited life expectancy or where the harms of treatment are greater than the benefits. B
14.23   Health care professionals may reasonably suggest more stringent A1C goals (such as <6.5% [<48 mmol/mol]) for selected children and adolescents if they can be achieved without significant hypoglycemia, excessive weight gain, negative impacts on well-being, or undue burden of care or in those who have nonglycemic factors that decrease A1C (e.g., lower erythrocyte life span). Lower goals may also be appropriate during the honeymoon phase. B
14.24   For children and adolescents with diabetes, CGM metrics derived from CGM use over the most recent 14 days (or longer) are recommended to be used in conjunction with or without A1C whenever possible. B
14.32   Consider setting an A1C goal of <6.5% (<48 mmol/mol)] for most children and adolescents with type 2 diabetes who have a low risk of hypoglycemia. For those at higher risk of hypoglycemia, A1C goals should be individualized as clinically appropriate. C
15.9     Due to increased red blood cell turnover, A1C is slightly lower during pregnancy in people with and without diabetes. Ideally, the A1C goal in pregnancy is <6% (<42 mmol/mol) if this can be achieved without significant hypoglycemia, but the goal may be relaxed to <7% (<53 mmol/mol) if necessary to prevent hypoglycemia. B
15.10   Continuous glucose monitoring (CGM) can help to achieve glycemic goals (e.g., time in range, time above range) A and A1C goal B in type 1 diabetes and pregnancy and may be beneficial for other types of diabetes in pregnancy. E
15.11   Recommend CGM to pregnant individuals with type 1 diabetes. A In conjunction with aims to achieve traditional pre- and postprandial glycemic goals, real-time CGM can reduce the risk for large-for-gestational-age infants and neonatal hypoglycemia in pregnancy complicated by type 1 diabetes. A
15.12   CGM metrics may be used in addition to but should not be used as a substitute for blood glucose monitoring to achieve optimal pre- and postprandial glycemic goals. E

The Endocrine Society also has recommendations for the use of CGM devices in their 2018 clinical practice guideline addressing this topic (Peters, 2018):

6. Real-time continuous glucose monitors in adult outpatients
6.1 We recommend real-time continuous glucose monitoring (RT-CGM) devices for adult patients with T1DM who have A1C levels above target and who are willing and able to use these devices on a nearly daily basis. (1⊕⊕⊕⊕)
6.2 We recommend RT-CGM devices for adult patients with well-controlled T1DM who are willing and able to use these devices on a nearly daily basis. (1⊕⊕⊕⊕)
6.3 We suggest short-term, intermittent RT-CGM use in adult patients with T2DM (not on prandial insulin) who have A1C levels 7% and are willing and able to use the device. (2⊕⊕OO)

Children and Adolescents (2011 guideline)

2.1 We recommend that RT-CGM with currently approved devices be used by children and adolescents with T1DM who have achieved glycosylated hemoglobin (HbA1c) levels below 7.0% because it will assist in maintaining target HbA1c levels while limiting the risk of hypoglycemia (1|⊕⊕⊕).
2.2 We recommend RT-CGM devices be used with children and adolescents with T1DM who have HbA1c levels ≤ 7.0% who are able to use these devices on a nearly daily basis (1|⊕⊕⊕O).
2.3 We make no recommendations for or against the use of RT-CGM by children with T1DM who are less than 8 years of age.
2.4 We suggest that treatment guidelines be provided to patients to allow them to safely and effectively take advantage of the information provided to them by RT-CGM (2|⊕OOO).
2.5 We suggest the intermittent use of CGM systems designed for short-term retrospective analysis in pediatric patients with diabetes in whom clinicians worry about nocturnal hypoglycemia, dawn phenomenon, and postprandial hyperglycemia; in patients with hypoglycemic unawareness; and in patients experimenting with important changes to their diabetes regimens [such as instituting new insulin or switching from multiple daily injections (MDI) to pump therapy] (2|⊕OOO).

It should be noted that recommendation 6.3 was graded “weak” and based on low quality evidence.

In 2023 the Endocrine Society published a clinical practice guideline addressing the management of individuals with diabetes at high risk for hypoglycemia (McCall, 2023). In this document they make the following recommendations:

Recommendation 1 We recommend continuous glucose monitoring (CGM) rather than self-monitoring of blood glucose (SMBG) by fingerstick for patients with type 1 diabetes (T1D) receiving multiple daily injections (MDIs). (1⊕⊕OO)
Recommendation 2 We suggest using real-time continuous glucose monitoring (CGM) and algorithm-driven insulin pumps (ADIPs) rather than multiple daily injections (MDIs) with self-monitoring of blood glucose (SMBG) three or more times daily for adults and children with type 1 diabetes (T1D). (2⊕⊕OO)
Recommendation 3 We suggest real-time continuous glucose monitoring (CGM) be used rather than no continuous glucose monitoring (CGM) for outpatients with type 2 diabetes (T2D) who take insulin and/or sulfonylureas (SUs) and are at risk for hypoglycemia. (2⊕OOO)
Recommendation 4 We suggest initiation of continuous glucose monitoring (CGM) in the inpatient setting for select inpatients at high risk for hypoglycemia. (2⊕OOO)
Recommendation 5 We suggest continuation of personal continuous glucose monitoring (CGM) in the inpatient setting with or without algorithm-driven insulin pump (ADIP) therapy rather than discontinuation. (2⊕OOO)

The Endocrine Society uses the following scheme to grade their recommendations (McCartney, 2022):

The AACE) and the ACE produced a consensus statement addressing outpatient glucose monitoring in 2016 (Bailey, 2016). This document makes the following recommendations for the use of CGM:

• Type 1 Adult: CGM recommended, particularly for patients with history of severe hypoglycemia, hypoglycemia unawareness and to assist in the correction of hyperglycemia in patients not at goal. CGM users must know basics of sensor insertion, calibration, and real-time data interpretation.
• Type 1 - Pediatric: Same as Adult Type 1. Both prevalence and persistent use of CGM is lower in children than adults. More in-depth training as well as more frequent follow-up is recommended to enable children to adopt the technology more successfully.
• Type 2 - Receiving insulin/ sulfonylureas, glinides: Data on CGM in T2DM are limited at this time. Trials assessing the use of CGM in T2DM patients are ongoing.
• Type 2 - Low risk of hypoglycemia: No recommendation.
• Gestational: Benefits of CGM in pregnant females with pre-existing diabetes are unclear based on current data; additional studies are ongoing. CGM during pregnancy can be used as a teaching tool, to evaluate glucose patterns, and to fine-tune insulin dosing. CGM in pregnancy can supplement BGM, in particular for monitoring nocturnal hypoglycemia or hyperglycemia and postprandial hyperglycemia.

The AACE and ACE published a position statement on the integration of insulin pumps and continuous glucose monitoring in patients with diabetes mellitus (Grunberger, 2018). This document states the following:

The AACE/ACE recommends that CGM be considered for all insulin-using patients, regardless of diabetes type. Insulin pump usage is recommended in patients with intensively managed insulin-dependent T1DM or T2DM (those who perform at least 4 insulin injections and 4 SMBG measurements daily). Integration of CGM and CSII may be considered in patients already on SII or appropriate for initiating CSII.

Personal CGM should ideally be considered in all patients with T1DM, especially those with a history of severe hypoglycemia, hypoglycemia unawareness, and to assist in the correction of hyperglycemia in patients not at goal. Of note, usage and persistence of usage of CGM is lower in pediatric patients. The benefits of CGM in patients with T2DM have not been investigated to the same degree. A key aspect of successful glycemic control with CGM, however, is patients’ ability to understand and respond to the data they receive in real time. Recent results show there is some variation in how patients adjust insulin therapy. Nonetheless, CGM users do rely on glucose rate of change arrows to adjust insulin delivery.

Appropriate candidates for pump therapy include:

• Patients with T1DM who are not at glycemic goal, despite adherence to maximum MDI, in particular
  • Those with erratic and wide glycemic excursions (including recurrent DKA)
  • Frequent severe hypoglycemia and/or hypoglycemia unawareness
  • Significant “dawn phenomenon,” extreme insulin sensitivity
• T1DM special populations (including preconception, pregnancy, children, adolescents, and competitive athletes)
• Patients with T1DM who feel CSII would help achieve and maintain glycemic targets
• Select patients with insulin-dependent T2DM with any or all of the following:
  • C-peptide positivity with suboptimal control on maximal basal/bolus injections
  • Substantial “dawn phenomenon”
  • Erratic lifestyle (e.g., frequent long-distance travel, shift work, and unpredictable schedules)
  • Severe insulin resistance
• Select patients with other DM types (e.g., postpancreatectomy).

Importantly, patients who are unable or unwilling to perform MDI, frequent SMBG, and carbohydrate counting; lack motivation to achieve tighter glucose control or have a history of nonadherence; have a history of serious psychological or psychiatric conditions; or have either substantial reservations or unrealistic expectations about pump therapy are not good candidates.

Use of CGM with integrated pump requires patient self-management. The ideal candidate must be willing and able to carry out tasks associated with using the system, self-monitor and react to collected data, and maintain frequent contact with the healthcare team. Intensive education is needed, and patients must be willing to complete the necessary training. Family support, particularly with pediatric patients, is paramount to success. The increased burden on patients and their families, as well as health-economic and ethical concerns, must be considered carefully, and this strategy may not be ideal for all patients.

Additionally, in 2018 the Endocrine Society published Advances in Glucose Monitoring and Automated Insulin Delivery: Supplement to Endocrine Society Clinical Practice Guidelines (Peters, 2018). In this document they make the following recommendations:

6.      Real-time continuous glucose monitors in adult outpatients
6.1    We recommend real-time continuous glucose monitoring (RT-CGM) devices for adult patients with T1DM who have A1C levels above target and who are willing and able to use these devices on a nearly daily basis. (1|⊕⊕⊕⊕)
6.2    We recommend RT-CGM devices for adult patients with well-controlled T1DM who are willing and able to use these devices on a nearly daily basis. (1|⊕⊕⊕⊕)
6.3    We suggest short-term, intermittent RT-CGM use in adult patients with T2DM (not on prandial insulin) who have A1C levels 7% and are willing and able to use the device. (2|⊕⊕OO)

In 2021 the AACE published clinical practice guidelines addressing the use of advanced technology in the management of persons with diabetes mellitus (Grunberger, 2021). Their recommendations in that document include the following:

R2.1.3   CGM is recommended for all individuals with problematic hypoglycemia (frequent/severe hypoglycemia, nocturnal hypoglycemia, hypoglycemia unawareness). Grade A; Intermediate-High Strength of Evidence; BEL 1
R2.1.4   CGM is recommended for children/adolescents with T1D. Grade A; Intermediate-High Strength of Evidence; BEL 1
R2.1.5   CGM is recommended for pregnant women with T1D and T2D treated with intensive insulin therapy. Grade A; Intermediate-High Strength of Evidence; BEL 1
R2.1.6   CGM is recommended for women with gestational diabetes mellitus (GDM) on insulin therapy. Grade A; Intermediate Strength of Evidence; BEL 1
R2.1.7   CGM may be recommended for women with GDM who are not on insulin therapy. Grade B; Intermediate Strength of Evidence; BEL 1
R2.1.8   CGM may be recommended for individuals with T2D who are treated with less intensive insulin therapy. Grade B; Intermediate Strength of Evidence; BEL 1
R2.2.1   The AGP may be utilized to assess glycemic status in persons with diabetes. Grade B; Low Strength of Evidence; BEL 1
R2.2.2   When using the AGP, a systematic approach to interpret CGM data is recommended:

1. Review overall glycemic status (eg, GMI, average glucose)
2. Check TBR, TIR, and TAR statistics, focusing on hypoglycemia (TBR) first. If the TBR statistics are above the cut-point for the clinical scenario (ie, for most with T1D >4% <70 mg/dL; >1% <54 mg/dL), the visit should focus on this issue. Otherwise, move on to the TIR and TAR statistics.
3. Review the 24-hour glucose profile to identify the time(s) and magnitude(s) of the problem identified.
4. Review treatment regimen and adjust as needed.
   Grade B; Low Strength of Evidence; BEL 1

R2.3.1   Real-time continuous glucose monitoring (rtCGM) should be recommended over intermittently scanned continuous glucose monitoring (isCGM) to persons with diabetes with problematic hypoglycemia (frequent/severe hypoglycemia, nocturnal hypoglycemia, hypoglycemia unawareness) who require predictive alarms/ alerts; however, the lifestyle of persons with diabetes and other factors should also be considered. Grade B; Low-Intermediate Strength of Evidence; BEL 1
R2.3.2   isCGM should be considered for persons with diabetes who meet 1 or more of the following criteria: Newly diagnosed with T2D Treated with nonhypoglycemic therapies Motivated to scan device several times per day at low risk for hypoglycemia, but desire more data than SMBG provides Grade D; Low Strength of Evidence/Expert Opinion of Task Force; BEL 4
R2.4.1   Diagnostic/professional CGM should be used in the management of persons with diabetes who meet 1 or more of the following criteria: Newly diagnosed with diabetes mellitus Not using CGM May have problematic hypoglycemia, but no access to personal CGM Persons with T2D treated with non-insulin therapies who would benefit from episodic use of CGM as an educational tool Persons who would like to learn more about CGM before committing to daily use Importantly, in those using “masked” or “blinded” diagnostic/professional CGM, they must have and continue using adjunctive SMBG to assist in daily diabetes self-care. Grade B; Intermediate Strength of Evidence; BEL 1
R2.9.1   Low-glucose suspend (LGS) is strongly recommended for all persons with T1D to reduce the severity and duration of hypoglycemia, whereas predictive low-glucose suspend (PLGS) is strongly recommended for all persons with T1D to mitigate hypoglycemia. Both systems do not lead to a rise in mean glucose, and lead to increased confidence and trust in the technology, more flexibility around mealtimes, and reduced diabetes distress for both persons with diabetes and caregivers. Therefore, anyone with frequent hypoglycemia, impaired hypoglycemia awareness, and those who fear hypoglycemia leading to permissive hyperglycemia should be considered for this method of insulin delivery. Grade A; High Strength of Evidence; BEL 1
R2.10.2 rtCGM is recommended for persons 65 years old with insulin-requiring diabetes to achieve improved glycemic control, reduce episodes of severe hypoglycemia, and improve QoL; however, glycemic goals should be individualized due to increased comorbidities and reduced capacity to detect and counter-regulate against severe hypoglycemia in this population. Grade A; Intermediate-High Strength of Evidence; BEL 1
R2.10.3 Clinicians should prescribe CGM as a tool to track glucose before, during, and after exercise in persons with diabetes; monitor the glycemic response to exercise; and help direct insulin and carbohydrate consumption to avoid hypoglycemia and hyperglycemia. When this technology is utilized as part of AID systems, it can reduce glycemic excursions during exercise. Grade A; Intermediate Strength of Evidence; BEL 1
R3.4.1   Clinicians should caution persons with diabetes who are using do-it-yourself systems that these devices have not undergone rigorous review by the FDA for safety and efficacy. Grade B; Low Strength of Evidence/Expert Opinion of Task Force; BEL 4

In 2022 the AACE published a new clinical practice guideline for developing a diabetes mellitus comprehensive care plan (Blonde, 2022). This document makes the following recommendations:

R 3.2      All persons who use insulin should use continuous glucose monitoring (CGM) or perform blood glucose monitoring (BGM) a minimum of twice daily and ideally before any insulin injection. More frequent BGM may be needed by persons who are taking multiple daily injections (MDI) injections, persons not at A1C targets, or those with history of hypoglycemia. Persons who do not require insulin or insulin secretagogue therapy may often benefit from BGM, especially to provide feedback about the effects of their lifestyle choices (diet and physical activity), and to assess response to pharmacologic therapy. Grade A; BEL 1
R 3.3      Real-time continuous glucose monitoring (rtCGM) or intermittently scanned continuous glucose monitoring (isCGM) is recommended for all persons with T1D, regardless of insulin delivery system, to improve A1C levels and to reduce the risk for hypoglycemia and DKA (see Fig. 6). Grade A; BEL 1
R 3.4      rtCGM or isCGM is recommended for persons with T2D who are treated with insulin therapy, or who have high risk for hypoglycemia and/or with hypoglycemia unawareness Grade A; BEL 1
R 15.6    Although inpatient CGM has not received regulatory approval, CGM may be useful in inpatient settings, while complying with institutional coverage guidelines and safety precautions. CGM may improve detection of severe hypoglycemic and hyperglycemic events, identify glucose trends and patterns, and improve satisfaction in persons with DM. Grade C; BEL 2
R 25       Persons with DM who are engaged in occupations with public safety implications, such as commercial drivers and pilots, have special management requirements for certification. CGM to predict hypoglycemia in real time and pharmacotherapy that minimizes hypoglycemia are recommended as effective strategies for persons with DM who work in these occupations. Grade A; BEL 1 and expert opinion of task force

In 2023 The AACE published a clinical endocrinology consensus statement on the comprehensive management algorithm for T2DM (Samson, 2023). This document stated “CGM is highly recommended to assist persons with diabetes in reaching goals safely.”

In 2023, the U.S. Department of Veterans Affairs and the U.S. Department of Defense released an updated clinical practice guideline for the management of T2DM mellitus. That document provided the following recommendation:

11. In insulin-treated adults with type 2 diabetes mellitus who are not achieving glycemic goals, we suggest real-time continuous glucose monitoring to decrease hypoglycemia and improve HbA1c. (Weak for | Reviewed, New-added

FDA Authorized/Approved Devices*

* This may not be an all-inclusive-list. Additional CGM devices may be FDA approved or cleared and available in the US.

Non-Prescription Devices (Note: This document does not address CGM devices approved for use without a prescription)

The FDA has granted 510K clearance for several CGM devices for use without a prescription (i.e., over the counter [OTC]). The purpose of these types of devices is to allow individuals to access glucose concentrations in real time without need for a needle stick for blood glucose monitoring. Use of a CGM device without a prescription, oversight of a medical provider, and use by individuals who do not require daily insulin therapy has not been adequately described in the peer-reviewed literature.

* This may not be an all-inclusive list. Additional CGM devices may be FDA approved or cleared and available in the US.

Continuous interstitial glucose monitoring (CGM) device: A device applied to the skin that contains a sensor implanted into the skin to measure glucose concentrations in the interstitial fluid. Such devices may be used to create a record of glucose concentrations over time to allow analysis by a medical professional. They may also measure and provide real-time glucose concentration data to allow an individual or automated insulin delivery system to adjust insulin delivery rates to provide better control of blood glucose concentrations.

External insulin infusion pumps: A device that is worn externally and attached to a temporary subcutaneous insulin catheter. An integrated computer controls a pump mechanism that administers insulin at a set rate or provide bolus injections as needed.

Flash CGM: A type of CGM device that requires the use of a device access glucose data from a sensor on a per-need basis. Glucose concentration data is not continuously visible with this type of device.

Glycemic: Having to do with blood sugar (glucose) levels.

Glycemic control: The ability of an individual’s body to control blood glucose concentrations within a specific physiologic range, either on its own or with the assistance of medical therapy.

Glycosylated hemoglobin (HbA1c) test: A laboratory test that provides the percentage of a specific type of modified hemoglobin in the blood. This test ascertains the level of diabetic blood glucose control over the past 3 to 4 months. The ADA has stated that an appropriate target for HbA1c concentrations in individuals with diabetes is 7% or lower (ADA, 2026).

Hyperglycemia: A condition characterized by excessively high blood glucose concentrations, generally considered greater than 150 mg/dL.

Hypoglycemia: : In patients with diabetes, defined as an episode of an abnormally low plasma glucose concentration (with or without symptoms) that expose the individual to harm. Serious hypoglycemia is generally considered a blood glucose level less than 54 mg/dL.

Intermittently scanned CGM (isCGM): A type of CGM device that provides intermittent, on-demand, visible glucose concentration data to the user.

Interstitial glucose: Glucose present in the fluid present in spaces between the tissue cells of the body.

Real time CGM (rtCGM): A type of CGM device that provides real-time, continuously visible glucose concentration data to the user.

Self-monitoring of blood glucose (SMBG): A method of glucose monitoring in which an individual obtains capillary blood samples, typically by fingerstick, and measures glucose levels using a portable blood glucose meter and test strips. SMBG provides point-in-time glucose values and is performed at intervals determined by the individual’s treatment regimen and clinical needs.

Time in range (TIR): The percentage of time that glucose values fall within a specified target range over a defined monitoring period, as measured by continuous glucose monitoring (CGM). In most adult populations with diabetes, the standard target range is 70-180 mg/dL, unless otherwise specified. TIR is used as a measure of overall glycemic control and variability.

Type 1 diabetes T1DM: A condition characterized by the impaired or inability of the pancreas to produce insulin. Sometimes known as ‘juvenile diabetes.’

Type 2 diabetes (T2DM): A condition characterized by a person’s body losing the ability to use insulin properly, a problem referred to as insulin resistance.

Peer Reviewed Publications:

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15. Choudhary P, Ramasamy S, Green L, et al. Real-time continuous glucose monitoring significantly reduces severe hypoglycemia in hypoglycemia-unaware patients with type 1 diabetes. Diabetes Care. 2013; 36(12):4160-4162.
16. Christiansen MP, Klaff LJ, Bailey TS, et al. A prospective multicenter evaluation of the accuracy and safety of an implanted continuous glucose sensor: The PRECISION study. Diabetes Technol Ther. 2019; 21(5):231-237.
17. Christiansen MP, Klaff LJ, Brazg R, et al. A prospective multicenter evaluation of the accuracy of a novel implanted continuous glucose sensor: PRECISE II. Diabetes Technol Ther. 2018; 20(3):197-206.
18. Cooke D, Hurel SJ, Casbard A, et al. Randomized controlled trial to assess the impact of continuous glucose monitoring on HbA1c in insulin-treated diabetes (MITRE Study). Diabet Med. 2009; 26(5):540-547.
19. Cox DJ, Banton T, Moncrief M, et al. Minimizing glucose excursions (GEM) with continuous glucose monitoring in type 2 diabetes: a randomized clinical trial. J Endocr Soc. 2020; 4(11):bvaa118. Erratum in: J Endocr Soc. 2020; 4(12):bvaa174.
20. Dehennis A, Mortellaro MA, Ioacara S. Multisite study of an implanted continuous glucose sensor over 90 days in patients with diabetes mellitus. J Diabetes Sci Technol. 2015; 9(5):951-956.
21. Deiss D, Irace C, Carlson G, et al. Real-world safety of an implantable continuous glucose sensor over multiple cycles of use: a post-market registry study. Diabetes Technol Ther. 2020; 22(1):48-52.
22. Dunn TC, Xu Y, Hayter G, Ajjan RA. Real-world flash glucose monitoring patterns and associations between self-monitoring frequency and glycaemic measures: a European analysis of over 60 million glucose tests. Diabetes Res Clin Pract. 2018; 137:37-46.
23. Ehrhardt NM, Chellappa M, Walker MS, et al. The effect of real-time continuous glucose monitoring on glycemic control in patients with type 2 diabetes mellitus. J Diabetes Sci Technol. 2011; 5(3):668-675.
24. Ferreira ROM, Trevisan T, Pasqualotto E, et al. Continuous glucose monitoring systems in noninsulin-treated people with type 2 diabetes: a systematic review and meta-analysis of randomized controlled trials. Diabetes Technol Ther. 2024; 26(4):252-262.
25. Floyd B, Chandra P, Hall S, et al. Comparative analysis of the efficacy of continuous glucose monitoring and self-monitoring of blood glucose in type 1 diabetes mellitus. J Diabetes Sci Technol. 2012; 6(5):1094-1102.
26. Furler J, O'Neal D, Speight J, et al. Use of professional-mode flash glucose monitoring, at 3-month intervals, in adults with type 2 diabetes in general practice (GP-OSMOTIC): a pragmatic, open-label, 12-month, randomised controlled trial. Lancet Diabetes Endocrinol. 2020; 8(1):17-26.
27. Gandhi GY, Kovalaske M, Kudva Y, et al. Efficacy of continuous glucose monitoring in improved glycemic control and reducing hypoglycemia: a systematic review and meta-analysis of randomized trials. J Diabetes Sci Technol. 2011; 5(4):952-965.
28. Haak T, Hanaire H, Ajjan R, et al. Flash glucose-sensing technology as a replacement for blood glucose monitoring for the management of insulin-treated type 2 diabetes: a multicenter, open-label randomized controlled trial. Diabetes Ther. 2017a; 8(1):55-73.
29. Haak T, Hanaire H, Ajjan R, et al. Use of flash glucose-sensing technology for 12 months as a replacement for blood glucose monitoring in insulin-treated type 2 diabetes. Diabetes Ther. 2017b; 8(3):573-586.
30. Irace C, Cutruzzolà A, Nuzzi A, et al. Clinical use of a 180-day implantable glucose sensor improves glycated haemoglobin and time in range in patients with type 1 diabetes. Diabetes Obes Metab. 2020; 22(7):1056-1061.
31. Jafri RZ, Balliro CA, El-Khatib F, et al. A three-way accuracy comparison of the Dexcom G5, Abbott Freestyle Libre Pro, and Senseonics Eversense continuous glucose monitoring devices in a home-use study of subjects with type 1 diabetes. Diabetes Technol Ther. 2020; 22(11):846-852.
32. Juvenile Diabetes Research Foundation Continuous Glucose Monitoring Study Group. Effectiveness of continuous glucose monitoring in a clinical care environment. Diabetes Care. 2010; 33(1):17-22.
33. Juvenile Diabetes Research Foundation Continuous Glucose Monitoring Study Group. The effect of continuous glucose monitoring in well-controlled type 1 diabetes. Diabetes Care. 2009; 32(8):1378-1383.
34. Kropff J, Choudhary P, Neupane S, et al. Accuracy and longevity of an implantable continuous glucose sensor in the PRECISE study: a 180-day, prospective, multicenter, pivotal trial. Diabetes Care. 2017; 40(1):63-68.
35. Lind M, Polonsky W, Hirsch IB, et al. Continuous glucose monitoring vs conventional therapy for glycemic control in adults with type 1 diabetes treated with multiple daily insulin injections: the GOLD randomized clinical trial. JAMA. 2017; 317(4):379-387.
36. Lind N, Christensen MB, Hansen DL, Nørgaard K. Comparing continuous glucose monitoring and blood glucose monitoring in adults with inadequately controlled, insulin-treated type 2 diabetes (Steno2tech Study): a 12-month, single-center, randomized controlled trial. Diabetes Care. 2024; 47(5):881-889.
37. Little SA, Speight J, Leelarathna L, et al. Sustained reduction in severe hypoglycemia in adults with type 1 diabetes complicated by impaired awareness of hypoglycemia: two-year follow-up in the HypoCOMPaSS randomized clinical trial. Diabetes Care. 2018; 41(8):1600-1607.
38. Martens T, Beck RW, Bailey R, et al; MOBILE Study Group. Effect of continuous glucose monitoring on glycemic control in patients with type 2 diabetes treated with basal insulin: a randomized clinical trial. JAMA. 2021; 325(22):2262-2272.
39. Mauras N, Beck R, Xing D, et al. A randomized clinical trial to assess the efficacy and safety of real-time continuous glucose monitoring in the management of type 1 diabetes in young children aged 4 to <10 years. Diabetes Care. 2012; 35(2):204-210.
40. Moon SJ, Kim KS, Lee WJ, et al. Efficacy of intermittent short-term use of a real-time continuous glucose monitoring system in non-insulin-treated patients with type 2 diabetes: a randomized controlled trial. Diabetes Obes Metab. 2023; 25(1):110-120.
41. Newman SP, Cooke D, Casbard A, et al. A randomised controlled trial to compare minimally invasive glucose monitoring devices with conventional monitoring in the management of insulin-treated diabetes mellitus (MITRE). Health Technol Assess. 2009; 13(28):iii-iv, ix-xi, 1-194.
42. Poolsup N, Suksomboon N, Kyaw AM. Systematic review and meta-analysis of the effectiveness of continuous glucose monitoring (CGM) on glucose control in diabetes. Diabetol Metab Syndr. 2013; 5(1):39.
43. Price DA, Deng Q, Kipnes M, Beck SE. Episodic real-time CGM use in adults with type 2 diabetes: results of a pilot randomized controlled trial. Diabetes Ther. 2021; 12(7):2089-2099.
44. Raccah D, Sulmont V, Reznik Y, et al. Incremental value of continuous glucose monitoring when starting pump therapy in patients with poorly controlled type 1 diabetes: the RealTrend study. Diabetes Care. 2009; 32(12):2245-2250.
45. Renard E, Riveline JP, Hanaire H, Guerci B; on behalf of the investigators of France Adoption Clinical Trial. Reduction of clinically important low glucose excursions with a long-term implantable continuous glucose monitoring system in adults with type 1 diabetes prone to hypoglycaemia: the France Adoption Randomized Clinical Trial. Diabetes Obes Metab. 2022; 24(5):859-867.
46. Saboo B, Sheth SV, Joshi S, et al. Use of ambulatory glucose profile for improving monitoring and management of T2DM. J Assoc Physicians India. 2018; 66(7):69-71.
47. Sanchez P, Ghosh-Dastidar S, Tweden KS, Kaufman FR. Real-world data from the first U.S. commercial users of an implantable continuous glucose sensor. Diabetes Technol Ther. 2019; 21(12):677-681.
48. Secher AL, Ringholm L, Andersen HU, et al. The effect of real-time continuous glucose monitoring in pregnant women with diabetes: a randomized controlled trial. Diabetes Care. 2013; 36(7):1877-1883.
49. Shields S, Thomas R, Durham J, et al. Continuous glucose monitoring among adults with type 2 diabetes receiving noninsulin or basal insulin therapy in primary care. Sci Rep. 2024; 14(1):31990.
50. Sierra JA, Shah M, Gill MS, et al. Clinical and economic benefits of professional CGM among people with type 2 diabetes in the United States: analysis of claims and lab data. J Med Econ. 2018, 21(3):225-230
51. Tamborlane WV, Beck RW, Bode BW, et al.; Juvenile Diabetes Research Foundation Continuous Glucose Monitoring Study Group. Continuous glucose monitoring and intensive treatment of type 1 diabetes. N Engl J Med. 2008; 359(14):1464-1476.
52. Tweden KS, Deiss D, Rastogi R, et al. Longitudinal analysis of real-world performance of an implantable continuous glucose sensor over multiple sensor insertion and removal cycles. Diabetes Technol Ther. 2020; 22(5):422-427.
53. Vigersky RA, Fonda SJ, Chellappa M, et al. Short- and long-term effects of real-time continuous glucose monitoring in patients with type 2 diabetes. Diabetes Care. 2012; 35(1):32-38.
54. Wada E, Onoue T, Kobayashi T, et al. Flash glucose monitoring helps achieve better glycemic control than conventional self-monitoring of blood glucose in non-insulin-treated type 2 diabetes: a randomized controlled trial. BMJ Open Diabetes Res Care. 2020; 8(1):e001115.
55. Wang X, Ioacara S, DeHennis A. Long-term home study on nocturnal hypoglycemic alarms using a new fully implantable continuous glucose monitoring system in type 1 diabetes. Diabetes Technol Ther. 2015; 17(11):780-786.
56. Yaron M, Roitman E, Aharon-Hananel G, et al. Effect of flash glucose monitoring technology on glycemic control and treatment satisfaction in patients with type 2 diabetes. Diabetes Care. 2019; 42(7):1178-1184.
57. Yeh HC, Brown TT, Maruthur N, et al. Comparative effectiveness and safety of methods of insulin delivery and glucose monitoring for diabetes mellitus: a systematic review and meta-analysis. Ann Intern Med. 2012; 157(5):336-347.
58. Yoo HJ, An HG, Park SY, et al. Use of a real time continuous glucose monitoring system as a motivational device for poorly controlled type 2 diabetes. Diabetes Res Clin Pract. 2008; 82(1):73-79.

Government Agency, Medical Society, and Other Authoritative Publications:

1. American Diabetes Association. Common Terms. Available at: https://diabetes.org/about-diabetes/common-terms?gclid=EAIaIQobChMIs8K9r4HYgwMVHFhHAR3g9Q5zEAAYASAAEgL61PD_BwE. Accessed on  February 26, 2026.
2. American Diabetes Association. Standards of Care in Diabetes-2026. Diabetes Care. 2026; 49(Suppl 1):S1-S371.
3. American Diabetes Association. Statistics about diabetes. Page updated November 2, 2023. Available at: https://diabetes.org/about-us/statistics/about-diabetes#:~:text=Prevalence%3A%20In%202019%2C%2037.3%20million,of%20the%20population%2C%20had%20diabetes.&text=Diagnosed%20and%20undiagnosed%3A%20Of%20the,and%208.5%20million%20were%20undiagnosed. Accessed on February 26, 2026.
4. Bailey TS, Grunberger G, Bode BW, et al. American Association of Clinical Endocrinologists and American College of Endocrinology 2016 outpatient glucose monitoring consensus statement. Endocr Pract. 2016; 22(2):231-261.
5. Blonde L, Umpierrez GE, Reddy SS, et al. American Association of Clinical Endocrinology Clinical Practice Guideline: developing a diabetes mellitus comprehensive care plan-2022 update. Endocr Pract. 2022; 28(10):923-1049.
6. Fonseca VA, Grunberger G, Anhalt H, et al.; Consensus Conference Writing Committee. Continuous glucose monitoring: a consensus conference of the American Association of Clinical Endocrinologists and American College of Endocrinology. Endocr Pract. 2016; 22(8):1008-1021.
7. Grunberger G, Bailey T, Camacho PM, et al.; Glucose Monitoring Consensus Conference Writing Committee. Proceedings from the American Association of Clinical Endocrinologists and American College of Endocrinology consensus conference on glucose monitoring. Endocr Pract. 2015; 21(5):522-533.
8. Grunberger G, Sherr J, Allende M, et al. American Association of Clinical Endocrinology Clinical Practice Guideline: The Use of Advanced Technology in the Management of Persons With Diabetes Mellitus. Endocr Pract. 2021; 27(6):505-537.
9. Handelsman Y, Bloomgarden ZT, Grunberger G, et al. American Association of Clinical Endocrinologists and American College of Endocrinology - clinical practice guidelines for developing a diabetes mellitus comprehensive care plan - 2015. Endocr Pract. 2015; 21(Suppl 1):1-87.
10. Klonoff DC, Buckingham B, Christiansen JS, et al. Continuous glucose monitoring: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011; 96(10):2968-2979.
11. Langendam M, Luijf YM, Hooft L, et al. Continuous glucose monitoring systems for type 1 diabetes mellitus. Cochrane Database Syst Rev. 2012;(1):CD008101.
12. McCall AL, Lieb DC, Gianchandani R, et al. Management of individuals with diabetes at high risk for hypoglycemia: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2023; 108(3):529-562.
13. McCartney CR, Corrigan MD, Drake MT, et al. Enhancing the Trustworthiness of the Endocrine Society's Clinical Practice Guidelines. J Clin Endocrinol Metab. 2022; 107(8):2129-2138.
14. Moy FM, Ray A, Buckley BS. Techniques of monitoring blood glucose during pregnancy for women with pre-existing diabetes. Cochrane Database Syst Rev. 2014;(4):CD009613.
15. Peters AL, Ahmann AJ, Battelino T, et al. Diabetes technology-continuous subcutaneous insulin infusion therapy and continuous glucose monitoring in adults: an Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2016; 101(11):3922-3937.
16. Samson SL, Vellanki P, Blonde L, et al. American Association of Clinical Endocrinology consensus statement: comprehensive type 2 diabetes management algorithm - 2023 update. Endocr Pract. 2023; 29(5):305-340.
17. United States Centers for Disease Control and Prevention. National Diabetes Statistics Report. May 15, 2024. Available at: https://www.cdc.gov/diabetes/php/data-research/index.html. Accessed on February 26, 2026.
18. United States Department of Veterans Affairs and United States Department of Defense. VA/DoD Clinical Practice Guideline For The Management of Type 2 Diabetes Mellitus. Version 6.0. 2023. Available at: https://www.healthquality.va.gov/guidelines/cd/diabetes/index.asp. Accessed on  February 26, 2026.
19. United States Food and Drug Administration. Premarket approval Dexcom G7 Continuous Glucose Monitoring (CGM) System. Available at: https://www.accessdata.fda.gov/cdrh_docs/pdf21/K213919.pdf. Accessed on February 26, 2026.
20. United States Food and Drug Administration. Premarket approval Eversense Continuous Glucose Monitoring System. Available at: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpma/pma.cfm?id=P160048. Accessed on February 26, 2026.
21. United States Food and Drug Administration. Premarket approval FreeStyle Libre 2 Flash Glucose Monitoring System; FreeStyle Libre 3 Continuous Glucose Monitoring System. Available at: https://www.accessdata.fda.gov/cdrh_docs/pdf22/K223435.pdf. Accessed on February 26, 2026.
22. United States Food and Drug Administration. Summary of safety and effectiveness data for the FreeStyle Libre Flash Glucose Monitoring System. September 27, 2017. Available at: https://www.accessdata.fda.gov/cdrh_docs/pdf16/P160030B.pdf. Accessed on February 26, 2026.

1. American Diabetes Association. 2020 Consumer guides. Available at: https://consumerguide.diabetes.org/. Accessed on February 24, 2026.
2. American Diabetes Association. Type 1 diabetes. Available at: https://diabetes.org/about-diabetes/type-1. Accessed on February 24, 2026.
3. American Diabetes Association. Understanding Type 2 diabetes. Available at: https://diabetes.org/about-diabetes/type-2. Accessed on February 24, 2026.
4. Centers for Disease Control and prevention. Type 1 Diabetes and Pregnancy. May 15, 2024. Available at: https://www.cdc.gov/diabetes/about/type-1-diabetes-pregnancy.html. Accessed on February 26, 2026.
5. Centers for Disease Control and prevention. Just Diagnosed With Type 1 Diabetes. May 15, 2024. Available at: https://www.cdc.gov/diabetes/signs-symptoms/just-diagnosed-type-1.html. Accessed on February 26, 2026.
6. Centers for Disease Control and prevention. Low Blood Sugar (Hypoglycemia). May 16, 2024. Available at: https://www.cdc.gov/diabetes/about/low-blood-sugar-hypoglycemia.html. Accessed on February 26, 2026.

Abbott Libre Rio
Abbot Lingo
Control IQ
Dexcom G6
Dexcom G7
Dexcom Stelo Glucose Biosensor
Enlite Sensor
Eversense 365 Continuous Glucose Monitoring System
Eversense E3 Continuous Glucose Monitoring System
Freestyle Libre 2
Freestyle Libre 3
Libre 14 Day Flash Glucose Monitoring System
MiniMed 530G
MiniMed 630G
MiniMed 670G
MiniMed 770G
MiniMed 780G
Paradigm REAL-Time System
Senseonics Eversense Continuous Glucose Monitoring System
Tandem t:slim X2 with Basal-IQ
Tandem t:slim X2 with Control-IQ

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