Chronic obstructive pulmonary disease (COPD) involves chronic inflammation that obstructs airflow from the lungs. Because COPD is a progressive condition, it steadily gets worse over time. Experts measure the progression by categorizing COPD into several stages using the Global Initiative for Chronic Obstructive Lung Disease (GOLD) system.

Newer guidelines have slightly changed this system so that the categorization references not just spirometry results but also the subjective severity of symptoms.

How the Stages Work

A medical professional uses a spirometer to measure how much air someone can breathe in and out, as well as how quickly they exhale that air. This produces two measurements: force vital capacity (FVC) and force expiratory volume in one second (FEV1). A person needs a ratio of under 0.7 FEV1/FVC to be diagnosed with COPD.

Doctors also use these numbers to grade the measurable severity of a person’s COPD from stages 1 to 4. The GOLD system now uses a lettering system from A to D, as well, to describe the subjective severity of symptoms and the frequency of exacerbations, which cause the symptoms to suddenly worsen. The stages:

  • A features less obstruction, fewer symptoms, and fewer exacerbations
  • B features less obstruction, more symptoms, and fewer exacerbations
  • C features worse obstruction, fewer symptoms, and more exacerbations
  • D features worse obstruction, more symptoms, and more exacerbations

patient measures his own lung capacity Phynart Studio/ Getty Images


Stage 1A and Stage 1B: Early COPD

The earliest and least severe period of COPD is stage 1. At this point, a person may not have any symptoms or even realize that anything is different. In stage 1, the FEV1 is between 80 and 100 percent of the predicted value. If someone does have symptoms at this stage, they may experience shortness of breath or general fatigue. Many people mistake these mild issues for allergies or the common cold.

Girl having respiration problems touching chest sitting on a couch in the living room at home AntonioGuillem/ Getty Images


Management of Stage 1A and Stage 1B

Because symptoms are mild in the earliest stages of COPD, the most effective action someone can take is to quit smoking or stop inhaling other hazardous particulates. This includes secondhand smoke, as well. Other management options include becoming more physically active, improving nutrition, and avoiding symptom triggers like dust, pollen, perfume, and pollutants in the air.

A doctor may prescribe a short-acting bronchodilator to help ease any breathing issues.

Doctors visiting senior milan2099/ Getty Images


Stage 2A and Stage 2B: Moderate COPD

COPD enters stage 2 once the FEV1 measurement is between 50 and 79 percent of the predicted value. At this point, the condition begins to affect daily life and will dramatically interfere with a person’s activity level.

Symptoms include a chronic cough, mild or severe fatigue, wheezing, and shortness of breath. Some people also have memory issues or general confusion.

senior man with wife at home coughing badly sturti/ Getty Images


Management of Stage 2A and Stage 2B

Because the condition’s severity increases in stage 2, the management methods also become a bit more elaborate. Typically, a person in stage 2 will undergo pulmonary rehabilitation under the guidance of physicians, nurses, and therapists. A rehab program might involve exercise training, breathing techniques, health education, and meetings with peer groups.

Doctors often use long-acting bronchodilators once their patients enter stage 2.

Mature adult man lying down on sofa in living room and using nebulizer during coronavirus pandemic. He is wearing sleepwear and using smartphone for communication. Shot indoor with a full frame mirrorless camera. selimaksan/ Getty Images


Stage 3C and Stage 3D: Severe COPD

Someone with stage 3 COPD experiences significantly worse symptoms, often with more frequent exacerbations. Their cough becomes more intense, and shortness of breath is extremely common.

Some people have headaches, especially after waking up. Their lips or nail beds may turn blue from lack of oxygen. Swelling may occur in the feet, ankles, and legs. To qualify for stage 3, the FEV1 value must fall between 30 and 49 percent.

Mature businesswoman having headache in office Westend61/ Getty Images


Management of Stage 3C and Stage 3D

Treating and managing COPD becomes much more difficult in stage 3. A pulmonary rehab program becomes a necessity, and it is vital to focus on exercising and maintaining a healthy diet. Doctors may perform frequent checkups to measure pulmonary function.

Though physicians may use supplemental oxygen at any stage of COPD, they most commonly begin using it in stage 3. Steroid inhalers are often necessary to decrease inflammation in the lungs.

Physician showing mature woman blue asthma inhaler Prostock-Studio/ Getty Images


Stage 4C and Stage 4D: Very Severe COPD

Though treatment will determine the speed of the progression, COPD will eventually progress to stage 4, which is diagnosed when the FEV1 is under 30 percent and there is severe damage to the lungs. At this point, the significant loss in lung function results in other organs being unable to perform their jobs.

The heart has to work harder to pump blood, leading to heart disease and other cardiac problems. Water retention also occurs as the heart gets weaker and the lower extremities may severely swell. Breathing becomes extremely difficult, which makes even small daily tasks a struggle. Weight loss and delirium are typical, as are many complications.

Doctor gives oxygen to an old woman pixelfit/ Getty Images


Management of Stage 4C and Stage 4D

Management strategies do not change much between stage 3 and stage 4 COPD. The doctor will encourage the individual to remain active under a professional’s guidance.

Doctors may use various bronchodilators or steroid inhalers as symptoms worsen. Some patients require lung volume reduction surgery to remove diseased lung tissue, while others may need lung transplants.

Home assistant doctor Holding Oxygen Mask Over women's Face mgstudyo/ Getty Images


Other Stages

Some groups use a slightly broader method of grading COPD to better recognize that the condition is extremely variable. Due to slightly adjusted FEV1 requirements, this method also includes stage 0 and stage U.

Stage 0 refers to a case where a person has normal spirometry, but complications like COPD are still possible. Stage U refers to undefined COPD, where a person does not quite qualify for a COPD diagnosis, but their FEV1 values and symptoms are consistent with the disease.

Mature adult man using nebulizer and looking outside through window. He is wearing blue colored hospital clothing. Shot indoor with a full frame mirrorless camera. selimaksan/ Getty Images


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