Stages of COPD Defined
According to the Global Initiative for Obstructive Lung Disease (GOLD), the severity of COPD is divided into four stages classified by spirometric measurement: Mild, moderate, severe and very severe. (See chart below).
Stage I: Mild COPD
During Stage I: Mild COPD, there may be mild airflow limitation but you may be unaware that lung function has started to decline. Forced expiratory volume in one second (FEV1) will be greater than or equal to 80% of the predicted normal values with an FEV1/FVC that is less than 70 percent. You may not yet have any COPD symptoms, or you may have symptoms of chronic cough and excessive mucus. People at this stage are not likely to associate symptoms with the disease process and therefore, rarely seek treatment.
Stage II: Moderate COPD
At Stage II: Moderate COPD, airflow limitation worsens and you may start to notice symptoms, particularly shortness of breath upon exertion along with cough and sputum production. Your FEV1 will be anywhere between 50% and 79% of the predicted normal values and your FEV1/FVC will be less than 70 percent. It is during this stage most people typically seek medical treatment.
Stage III: Severe COPD
Once the disease has advanced to Stage III: Severe COPD, limitation of airflow significantly worsens, shortness of breath becomes more evident and COPD exacerbations are common. Your FEV1 will be between 30% and 49% predicted and your FEV1/FVC will be less than 70 percent. If you reach this stage, you may notice a decrease in your activity tolerance and an increase in fatigue-ability.
Stage IV: Very Severe COPD
By the time a COPD patient reaches Stage IV: Very Severe COPD, their quality of life is greatly impaired and COPD exacerbations can be life threatening. Airflow limitation is severe (FEV1 less than 30% predicted or less than 50% predicted with chronic respiratory failure ) and your FEV1/FVC will be less than 70 percent. Chronic respiratory failure is often present at this stage, and may lead to complications with your heart, such as cor pulmonale and/or eventually, death.
Who Needs Spirometry?
Being a current or former smoker places you at high risk for COPD. That said, if you still smoke, you are strongly encouraged to quit. Additionally, if you have any COPD-related respiratory symptoms, like shortness of breath, increased mucus, or a cough that won't go away, you should talk with your doctor about getting a spirometry test to confirm or negate a diagnosis of COPD.
Changing the Outcome of Your Disease
It is important that COPD patients understand that the stages defining COPD severity are only guidelines. What is more important is how well you take care of yourself and how you feel.There are certain steps that you can take to help keep your COPD from advancing and to ultimately change the course of your disease. Read more about them in How to Keep Your COPD From Getting Worse.
| GOLD Spirometric Criteria for COPD Severity | ||
| I. Mild COPD | * FEV1/FVC < 0.7 * FEV1 > or = 80% predicted | At this stage, the patient is probably unaware that lung function is starting to decline |
| II. Moderate COPD | * FEV1/FVC < 0.7 * FEV1 50% to 79% predicted | Symptoms during this stage progress, with shortness of breath developing upon exertion. |
| III. Severe COPD | * FEV1/FVC < 0.7 * FEV1 30% to 49% predicted | Shortness of breath becomes worse at this stage and COPD exacerbations are common. |
| IV. Very Severe COPD | * FEV1/FVC < 0.7 * FEV1 < 30% predicted or FEV1 < 50% predicted with chronic respiratory failure | Quality of life at this stage is gravely impaired. COPD exacerbations can be life threatening. |
Source:
Global Initiative for Obstructive Lung Disease. 2009 Update.
