Acupoint Herbal Patching for Asthma: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Acupoint herbal patching (AHP), which involves local point stimulation with a herbal medicine patch, has long been used to treat patients with asthma in East Asian countries. However, its evidence is equivocal. This systematic review aims to summarize and critically evaluate the efficacy and safety of AHP for asthma. A literature search was conducted in PubMed, EMBASE, the Cochrane library, and the China National Knowledge Infrastructure for studies published on or before April 2014, which were randomized controlled trials (RCTs) examining AHP therapy by itself or in combination with other treatments in asthma patients. Trials needed to report pulmonary function outcomes to be included in analyses. The risk of bias of included studies was assessed using the Cochrane risk of bias assessment tool. For statistical pooling, risk ratio, mean difference (MD), or standardized MD was calculated with 95% confidence intervals (CIs) in a random-effects model. We ultimately included 16 RCTs with 1287 asthmatic patients in analyses. Treatment with AHP improved forced expiratory volume in 1 second (FEV1) by 13% (MD = 12.99%, 95% CI 5.17%-20.81%) and asthmatic symptoms by 60% (risk ratio of unchanged or getting worse symptoms with AHP = 0.4, 95% CI 0.27-0.58) over that observed with placebo. However, evidence is limited due to the heterogeneity and paucity of data. When added to conventional therapies, AHP significantly improved the FEV1/forced vital capacity ratio by 11.6% (95% CI 8.49%-14.79%) and reduced the risk of asthmatic symptoms by 69% (95% CI 0.16-0.58). Compared with conventional medication, AHP significantly improved FEV1 (standardized MD = 0.46, 95% CI 0.05-0.87), but a substantial heterogeneity was detected (I-2 = 53%). When added to Chinese herbal medicine, there were no additional benefits of AHP on pulmonary function or global symptom improvement. No serious adverse events were associated with AHP. Evidence for AHP efficacy is encouraging, but not conclusive, because of clinical diversity and the high risk of bias in the examined studies. Further clinical and basic research is needed to determine the role of AHP in lung function and symptom improvement in patients with asthma.