Legend: SD: standard deviation, CHM: Chinese Herbal Medicine, RP: routine pharmacotherapy, mths: months, Gps: groups, Salb./Ipra.: salbutamol/ipratropium (inhaled), exe.: pulmonary exercise, Ipra.: ipratropium (inhaled), oxy.: oxygen therapy, RP(+p.r.): routine pharmacotherapy (pharmacotherapy plus pulmonary rehabilitation), RP (guidelines): routine pharmacotherapy (adjusted for severity according to guidelines), Theo.(+p.r.): oral theophylline (plus pulmonary rehabilitation), Salm./Flu.: salmeterol/fluticasone (inhaled), Ami./Bro./Chlo.: compound oral medication which contained aminophylline, bromhexine and chlorphenamine, Theo.: theophylline (oral), Muc.: Mucosolvan (oral), LABAs: long-acting β2 agonists (inhaled), Salb.: salbutamol (inhaled).