Traditional Chinese medicine for acute mountain sickness prevention: A systematic review and meta-analysis of randomized controlled trials

Objective: To evaluate the efficacy of traditional Chinese medicine (TCM) for preventing acute mountain sickness (AMS). Methods: We included randomized controlled trials (RCTs) which evalueded the effect of TCM for preventing AMS, compared with a placebo, no treatment or acetazolamide. The literature was searched in 6 major databases. RevMan 5.4 software was used for the meta-analysis. The relative risk for discrete variables and the mean difference for continuous variables with 95% confidence intervals (CIs) were applied to express the effect size. The risk of bias in the included studies was evaluated using the Cochrane risk assessment tool 2.0 (RoB 2.0), and the evidence certainty was assessed using the Grading of Recommendations Assessment and the Development and Evaluation (GRADE) approach. Results: Twenty RCTs involving 3015 participants and 16 TCM patent drugs were included. The overall risk of bias in the majority of studies (15/20) was of some concerns. In terms of the AMS incidence, Rhodiola rosea (R. rosea, Hong Jing Tian) and Ginkgo biloba (G. biloba, Yin Xing Ye) were equivalent to the placebo/no treatment [RR (95% CI): 0.66 (0.43–1.01), 0.82 (0.63–1.06), respectively]. The AMS incidence in the G. biloba group was higher than that in the acetazolamide group [RR (95% CI): 2.92 (1.69–5.06)]. In terms of improving the AMS symptom score on days 1 and 3 in the plateau, R. rosea and G. biloba were superior to the placebo or no treatment [MD (95% CI): -0.98 (-1.71, -0.25), -2.05 (-3.14, -0.95), respectively]. The other 14 Chinese patent medicines were evaluated in a single trial, and the majority of the results were negative. The subgroup analysis showed that the effect of R. rosea was related to the intervention time, way of ascending, and altitude. Conclusion: R. rosea and G. biloba were effective in improving AMS symptoms but had no effect in reducing the AMS incidence. There was insufficient evidence to support the use of other TCM patent drugs to prevent AMS. More randomized double-blind placebo-controlled trials are warranted to evaluate and screen effective Chinese patent medicines for AMS prevention.