Chronic Obstructive Pulmonary Disease (COPD)

COPD is a progressive, irreversible inflammatory disease of the lungs that makes it difficult to breathe. Cigarette smoking is the most common cause of COPD. Common symptoms include a persistent cough, wheezing, production of phlegm, shortness of breath, and a feeling of tightness in your chest, though these symptoms may not be noticeable until you’re in the later stages of the disease. While COPD is not curable, it is a preventable and treatable illness. The earlier you start treatment, the better your prognosis.

Frequently Asked Questions

  • What are the symptoms of COPD?

    COPD is often asymptomatic until significant damage to the lungs has occurred. When symptoms do start to appear, shortness of breath is often the first one. Patients may feel like they are hungry for air or working hard to breathe. Other possible symptoms of COPD include fatigue, wheezing, a chronic cough, mucous (phlegm) production, and chest tightness.

  • What causes COPD?

    Cigarette smoking, whether in the past or present, is the most common cause of COPD. Exposure to secondhand smoke, air pollution, chemical fumes (often in the workplace), or dust may also cause COPD. Rarely, a genetic disorder called alpha-1-antitrypsin (AAT) deficiency is the culprit.

  • How is COPD diagnosed?

    If a patient has symptoms suggestive of COPD (e.g., persistent or worsening shortness of breath), the diagnosis can be confirmed with a pulmonary function test called spirometry. Laboratory and imaging tests may also be ordered to rule out alternative diagnoses like heart failure or pulmonary fibrosis.

  • What does COPD stand for?

    COPD stands for chronic obstructive pulmonary disease. It is a general term that includes various progressive lung diseases, most commonly chronic bronchitis (irritation of the bronchial tubes) and emphysema (destruction of the air sacs). 

  • What are the four stages of COPD?

    The GOLD system, which stands for Global Initiative for Chronic Obstructive Lung Disease, classifies COPD into the following four stages: 

    GOLD 1: Mild

    GOLD 2: Moderate

    GOLD 3: Severe

    GOLD 4: Very Severe

    These stages are based on forced expiratory volume (FEV1) readings, which is the amount of air a person can forcefully breathe out in one second. 

  • How long can you live with COPD?

    COPD is associated with a reduced lifespan. While there is no way to determine a person's exact life expectancy, it can be predicted using a tool called the BODE index. This index utilizes four measures: body mass index (BMI), airway obstruction, dyspnea (shortness of breath), and exercise tolerance.

Key Terms


Page Sources
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  1. Miravitlles M, Ribera A. Understanding the impact of symptoms on the burden of COPD. Respir Res. 2017;18(1):67. doi:10.1186/s12931-017-0548-3

  2. American Lung Association. How lungs work: the respiratory system. Updated April 2020.

Additional Reading