The Effects of Safflower Yellow on Acute Exacerbation of Chronic Obstructive Pulmonary Disease: A Randomized, Controlled Clinical Trial

Table 1

Classification of airflow limitation in patients with COPD.

FEV1/FVC <70% (FEV1 after inhalation of bronchodilators)
GOLD1: Mild	FEV1 ≥80% predicted
GOLD2: Medium	50%⩽ FEV1% <80% predicted
GOLD3: Severe	30%⩽ FEV1% <50% predicted
GOLD4: Extremely severe	FEV1% <30% predicted