Clinical efficacy and safety of Chinese herbal medicine versus placebo for the treatment of chronic obstructive pulmonary disease: A systematic review and meta-analysis

Objective Randomized clinical trials and published meta-analyses assessing the clinical effectiveness of Chinese herbal medicine (CHM) on the treatment of stable chronic obstructive pulmonary disease (COPD) yielded inconsistent results in terms of disease outcomes, in which the design of placebo-controlled studies can contribute to the heterogeneity. This study aimed to evaluate the efficacy and safety of CHM compared to placebo on the treatment of stable COPD, to provide robust evidence for the use of CHM in COPD. Methods Nine electronic databases were searched from inception to October 1, 2019 to identify placebo controlled randomized trials of CHM for the treatment of stable COPD and studies in English or Chinese were included. The primary outcomes were symptom score (CAT score), quality of life (SGRQ) and frequency of acute exacerbations. The secondary outcomes included lung function, clinical total effective rate and adverse events. The selection of studies, data extraction and coding and assessment of risk of bias of the included studies were conducted by two reviewers independently. Mean difference (MD) was used to analyze continuous variable and relative risk ratio (RR) for dichotomous data. Results A total of eleven studies involving 1223 patients were included. While maintaining routine western pharmacotherapies (WP), CHM had significant advantage over the treatment of placebo in improving CAT score (MD -3.93; 95 %CI -6.01 to -1.85) and SGRQ score (MD -6.20; 95 %CI -10.13 to -2.28), reducing the frequency of acute exacerbations (MD -0.78; 95 %CI -1.40 to -0.16) and improving clinical effective rate (RR 1.29; 95 %CI 1.14 to 1.45), but had no significant effect on improving FEV1%pred (MD 8.18; 95 %CI -4.22 to 20.58). High heterogeneity was found for the changes in exacerbation frequency and FEV1%pred. No serious adverse events related to CHM were reported. Conclusions This meta-analysis of placebo-controlled RCTs demonstrated that the use of CHM in addition to WP could alleviate clinical symptoms, improve quality of life and clinical efficiency and reduce the frequency of exacerbations, which could be an alternative approach for treatment adjustment of COPD. CHM was a relatively safe treatment. These findings need to be verified in future with high-quality clinical trials.