Table 2.

Classification of the severity of obstruction and the clinical severity of chronic obstructive pulmonary disease (COPD)

	Severity of obstruction (assessed after bronchodilation)	Clinical severity of COPD
Mild	FEV1 ≥ 80% predicted	Good quality of life (CAT® < 10), no frequent exacerbations and FEV1 >50% predicted
Moderate	50% ≤ FEV1 < 80%	One of the following: • FEV1 < 50% predicted • At least two exacerbations a year or one hospitalization because of COPD • COPD has a medium impact on life (e.g. CAT® ≥ 10 points) or causes poor quality of life or impaired exercise tolerance
Severe	30% ≤ FEV1 < 50%
Very severe	FEV1 < 30%	One of the following: • FEV1 < 30% predicted • Chronic respiratory failure • Frequent exacerbations or hospitalizations regardless of treatment to COPD • COPD has a high or very high impact on life (e.g. CAT® ≥ 20 points) or causes very poor quality of life or exercise tolerance