An Overview of Systematic Reviews of Chinese Herbal Medicine in the Treatment of Migraines

Background: In the past, systematic reviews (SRs) and meta-analyses (MAs) have been used to assess the efficacy of Chinese herbal medicine (CHM) in the treatment of migraines. However, robust conclusions have not yet been determined because of variations in the methodological and evidence quality of these SRs/MAs. Objectives: We aimed to assess the methodological and reporting quality of SRs/MAs and evaluate the available evidence of the efficacy of CHM treatment of migraines. Methods: We searched eight electronic databases from inception until 10 January 2022, without language restrictions. Two researchers were independently responsible for study screening and data extraction. The methodological and reporting quality of SRs/MAs were assessed using A Measurement Tool to Assess Systematic Reviews (AMSTAR) 2 and Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). The evidence quality of included SRs/MAs was evaluated by Grading of Recommendations Assessment, Development and Evaluation (GRADE). In addition, a descriptive analysis of the included SRs/MAs was included. Results: Sixteen SRs/MAs, including 69 outcomes, were finally included in this overview. Data synthesis of the included SRs/MAs outcomes showed that CHM plus Western medicine (WM) was beneficial in the improvement of migraines. In comparison, there was conflicting evidence for the effectiveness of CHM used alone. CHM was better than WM in improving responder rate and acute medication usage and was superior to placebo in improving migraine days, responder rate, and migraine duration. However, there was insufficient evidence to verify the effectiveness of CHM for migraine treatment regarding pain severity and migraine frequency. All the included SRs/MAs showed extremely low methodological and reporting quality. The results of the GRADE system indicated that the quality of most of the pooled evidence was very low. Conclusions: CHM may be beneficial in improving migraines and can be used as a complementary therapy. However, we should treat the conclusions of the evaluated SRs/MAs cautiously because of the low quality of evidence. Future SRs/MAs should focus on improving methodological and reporting quality. High-quality randomized controlled trials (RCTs) are needed to provide strong evidence for the efficacy of CHM treatment of migraines.