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