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A Guide to the Four COPD Stages

July 19, 2019

Chronic obstructive pulmonary disease (COPD) is a progressive lung disease, meaning it worsens over time. It results in restricted airflow into the lungs, which makes breathing difficult. COPD can have numerous causes, including smoking and long-term exposure to air pollutants, as well as a rare genetic disorder. Patients generally go through four stages of the disease, from least to most severe. Lung function tests are the most common method to determine these stages.

Understanding the Tests

Doctors take two measurements during a breathing test to judge how far a patient’s COPD has progressed. The measurements are taken using a device called a spirometer.

  • Forced vital capacity (FVC) measures how much air a patient can breathe out quickly and forcefully after a deep breath.
  • Forced expiratory volume (FEV1) measures how much air is blown out in the first second of the test.
What Test Results Mean

By comparing the FEV1 measurement to the FVC measurement, a doctor can determine the percentage of the total lung capacity a patient can breathe out in one second. That ratio can help diagnose the specific type of COPD involved — emphysema, chronic bronchitis or both. The FEV1 score is compared to average figures from healthy individuals to help determine the COPD stage, as follows:

  • Stage 1 (Mild COPD) is defined with FEV1 results of 80% or higher than those of healthy individuals. Patients in Stage 1 might experience coughing or increased mucus but might not know they have COPD. At this stage, your doctor might suggest breathing exercises and lifestyle changes, like quitting smoking if you’re a smoker.
  • Stage 2 (Moderate COPD) is defined with FEV1 results between 50% and 80% of those of healthy individuals. Symptoms include shortness of breath, wheezing and excess mucus. Your doctor might prescribe bronchodilator medication to help open your airways.
  • Stage 3 (Severe COPD)is defined with FEV1 results between 30% and 50% of those of healthy individuals. COPD at this stage can have a big impact on quality of life. Symptoms can make it difficult to perform daily tasks. Your doctor might prescribe corticosteroids to help reduce inflammation, along with a combination inhalers and other medications.
  • Stage 4 (Very severe COPD) is defined with FEV1 results below 30%. This is also called end-stage COPD. At this point, flare-ups and breathing problems can become life-threatening. Low blood oxygen can lead to several serious health conditions, including hypoxia, hypoxemia and cyanosis. Your doctor might prescribe oxygen therapy to lessen such risks.
Additional Tests

To help determine possible treatments, physicians also want to know how a person’s disease might be affecting their daily life. This is accomplished through a number of additional tests that determine a patient’s BODE Index, which includes:

  • Body mass index (FVC), which compares weight to height. This can help determine any special nutritional needs.
  • Obstruction of airflow, using FEV1 and FVC test results.
  • Dyspnea, which means breathing difficulty. This helps doctors understand how shortness of breath could be affecting quality of life.
  • Exercise capacity, measured in a 6-minute walking test. This shows how much exercise you can tolerate before symptoms begin.