Table 2.

COPD diagnosis and severity based on spirometry outcomes (GOLD 20115)

Diagnosis	Post-dose parameters
No disease	FEV1/FVC ≥ 0.70
COPD GOLD stage:
Stage I: Mild	FEV1/FVC < 0.70 FEV1 ≥ 80% predicted
Stage II Moderate:	FEV1/FVC < 0.70 50% ≤ FEV1 < 80% predicted
Stage III: Severe	FEV1/FVC < 0.70 30% ≤ FEV1 < 50% predicted
Stage IV: Very Severe	FEV1/FVC < 0.70 FEV1 < 30% predicted or FEV1 < 50% predicted plus chronic respiratory failure

FEV₁ forced expiratory volume in one second; FVC forced vital capacity; respiratory failure: arterial partial pressure of oxygen (PaO₂) less than 8.0 kPa (60 mmHg) with or without arterial partial pressure of CO₂ (PaCO₂) greater than 6.7 kPa (50 mmHg) while breathing air at sea level