Stage 4 COPD was a former diagnostic term referring to the final stages of chronic obstructive pulmonary disease (COPD). Stage 4 COPD symptoms can include breathing difficulties, and blood oxygen levels may be dangerously low.

Previously, the Global Initiative for Chronic Obstructive Lung Disease (GOLD) indicated four stages of COPD, ranging from mild to severe, based on a person’s FEV1. FEV1 stands for forced expiratory volume in 1 second. It measures the amount of air a person can exhale in 1 second, which indicates how well their lungs function.

In new guidelines, people with COPD now receive two scores. They include a grade between one and four, representing the airflow limitation, and a letter from A to D, indicating a person’s symptom and exacerbation history.

Continue reading to learn more about COPD symptoms, stages and grades, causes, diagnoses, and treatment.

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The symptoms that a person with COPD has do not only depend on the GOLD grade they receive. They typically also depend on how well they control this condition.

However, symptoms are more likely to occur and be severe if a person has higher GOLD grades.

A person may experience more severe symptoms as COPD progresses into the late stages. These may include:

GOLD previously designated four stages of COPD, from mild to severe, which depended on a person’s FEV1.

Stage one indicated a slight loss of function, while stage four showed a severe loss.

An individual with stage one COPD has an FEV of 80%, meaning their lung function is 20% or less impaired.

People with stage four COPD have an FEV of less than 30%, meaning their lungs are severely affected and low-functioning.

New GOLD guidelines

The revised GOLD guidelines provide a person with two scores. They give a grade between one and four to indicate airflow limitation and a letter between A and D to indicate their symptoms and history of moderate-to-severe exacerbation. Instead of using a single stage, people with COPD now receive a grade and a group classification.

For example, in a severe case where an individual has an FEV1 score lower than 30% and has experienced moderate-to-serious exacerbation, doctors classify them as GOLD grade 4, group D.

A person with an FEV1 score of at least 80 who has experienced at least moderate exacerbation would be GOLD grade 1, group D.

COPD symptoms are likely to worsen and become more severe as the disease progresses from early to late stage. They may include:

  • a persistent cough that produces mucus
  • tightness in the chest
  • shortness of breath
  • whistling or wheezing sound when breathing

As COPD progresses, more severe symptoms may include:

  • weight loss
  • swollen feet or ankles
  • low muscle endurance
  • fingernails or lips turning blue or grey
  • being less mentally alert
  • fast heartbeat
  • difficulty catching breath and talking
  • treatment for COPD is unsuccessful

COPD develops when the airways and lungs become inflamed and damaged. There are various potential causes.


Smoking is the leading cause of COPD, with experts believing it causes 9 in 10 cases. The harmful chemicals in cigarettes can damage the lining of the airways and lungs. Therefore, stopping smoking can help prevent COPD from progressing.


A person is more likely to develop COPD if they have a close family relative with the condition. Around 1 in every 100 individuals with COPD have a genetic tendency towards the disease, called alpha-1- antitrypsin deficiency. The substance they are deficient in, alpha-1-antitrypsin, protects the lungs, and those without it are more vulnerable to lung damage.


People over 65 years of age are more likely to have COPD than younger people.

Exposure to chemicals and fumes

If a person encounters certain chemicals, dust, or fumes, usually in the workplace, they may damage their lungs and be at greater risk of COPD. Substances linked to the condition include:

  • silica dust
  • coal dust
  • welding fumes
  • grain and flour dust

Environmental exposure

If an individual has long-term exposure to air pollution over a long period, research suggests this may increase their COPD risk.

There is no single test to diagnose COPD. A doctor diagnoses the condition based on its symptoms, the individual’s medical and family history, and test results.

A healthcare professional may also ask questions to determine a person’s level of risk of developing COPD, such as whether they smoke or if they have come into contact with lung irritants such as dangerous fumes or chemicals. They may then perform other tests.


Spirometry is a painless test. It involves a person breathing in deeply and then blowing out as hard as possible into a tube connected to a machine called a spirometer.

This device measures how much air the person breathes out and how fast they can blow air out. A doctor may ask the person to inhale medications to help open their airways and then blow into the tube again. They will then compare the results before and after taking the medicine.

Spirometry can help indicate the level of lung function and may help detect COPD before symptoms develop. A doctor may also use the results to determine the severity of COPD to set treatment goals.

Other tests

A doctor may recommend more tests, including the two below.

Arterial blood gas test

This test measures the oxygen in a person’s blood using a sample from an artery. A doctor can use the results of this test to help determine the severity of COPD.

A CT scan or chest X-ray

A doctor can use these tests to see images of structures inside the chest, lungs, heart, and blood vessels. The tests may show signs of COPD or help indicate whether a person’s symptoms are from another condition, such as heart failure.

There are various treatments a doctor may advise for COPD. These may include the following.


A doctor prescribes medication based on the severity of a person’s COPD. They commonly prescribe bronchodilators to relax the muscles around the airways and make breathing easier. An individual takes this medication through an inhaler.

A doctor may also prescribe a short-acting bronchodilator for mild COPD that lasts between 4–6 hours, and the person can use it as needed. Additionally, healthcare professionals can prescribe a long-acting bronchodilator for more severe COPD, lasting about 12 hours for daily use.

Doctors may also prescribe a steroid in combination with bronchodilators to ease airway inflammation.

Oxygen therapy

A person with severe COPD and low blood oxygen levels may benefit from oxygen therapy. This treatment involves a person breathing oxygen through a mask or nasal prongs.

Lifestyle adjustments

Stopping smoking is the most important and effective step a person can take to treat COPD. For help with quitting smoking, people can call the National Cancer Institute’s Smoking Quitline for free: 1-877-44U-QUIT (1-877-448-7848).

People with COPD should also avoid places with fumes, chemicals, and dust that they may inhale, as well as second-hand smoke from others.


This is usually a final option for individuals who find that other treatments are not effective. There are different surgeries a person with COPD may have, including:

  • Lung volume reduction surgery: Involves a surgeon removing damaged tissue from the lungs.
  • Bullectomy: Doctors remove bullae from the lungs, which are the air spaces that appear as COPD destroys the walls of the air sacs. Bullae interfere with breathing.
  • Lung transplant: Surgeons remove a person’s damaged lung and replace it with a healthy lung from a donor.

Stage 4 COPD is a former diagnostic term that doctors used to describe late-stage, severe COPD. New guidelines classify COPD using two scores: a grade between one and four, representing the airflow limitation, and a letter from A to D, relating to a person’s symptom and exacerbation history.

People with severe COPD may experience various symptoms, including hospitalizations, bacterial infection, pulmonary hypertension, and severe breathlessness. These symptoms can become more serious as the disease progresses.

The causes of COPD include exposure to chemicals and fumes, increasing age, smoking, and genetics.

Doctors diagnose the condition using physical examinations, spirometry tests, and other tests such as X-rays.

Treatment for COPD includes oxygen therapy, surgery, medication, and lifestyle changes.