The four stages of Chronic Obstructive Pulmonary Disease (COPD) are:
- Stage 1 – Mild COPD: In this stage, the airflow limitation is mild, with a FEV1 (Forced Expiratory Volume in one second) of 80% or higher. There may be a persistent cough and phlegm production, but the symptoms are usually not severe enough to interfere with daily activities.
- Stage 2 – Moderate COPD: In this stage, the airflow limitation worsens, with a FEV1 between 50% and 80%. Shortness of breath becomes more noticeable, and the cough and phlegm production become more persistent. Daily activities may become more difficult.
- Stage 3 – Severe COPD: In this stage, the airflow limitation is severe, with a FEV1 between 30% and 50%. Shortness of breath becomes even more severe, and it may be difficult to perform daily activities such as dressing and bathing without assistance.
- Stage 4 – Very Severe COPD: In this stage, the airflow limitation is very severe, with a FEV1 below 30%. The person may experience respiratory failure, and their quality of life is significantly impaired. They may require oxygen therapy and hospitalization.