Efficacy of Acupuncture for Tension-Type Headache Prophylaxis: Systematic Review and Meta-Analysis with Trial Sequential Analysis

Background: Acupuncture has been shown to reduce tension-type headache (TTH) frequency in previous meta-analyses, but repeated significance testing renders a solid conclusion on its efficacy. We aimed to verify the effectiveness of acupuncture in reducing TTH frequency by meta-analysis and trial sequential analysis (TSA). Methods: Ovid Medline, Embase, and Cochrane Library were searched until September 29, 2022. Randomized controlled trials comparing acupuncture with sham acupuncture, no acupuncture (received usual care or waiting list), or other active therapies in adults with TTH were included. The primary outcome was TTH frequency. The secondary outcomes were responder rate and adverse event rate. Findings: Fourteen studies involving 2795 participants were included. Acupuncture had more reduction than sham acupuncture in TTH frequency, both at the end of treatment (standardized mean difference [SMD] −0.80, 95% confidence interval [CI] −1.36 to −0.24, P=0.005) and the follow-up period (SMD −1.33, 95% CI −2.18 to −0.49, P=0.002), while TSA showed the included sample size did not exceed required information size (RIS). Acupuncture was superior over no acupuncture after treatment (SMD −0.52, 95% CI −0.63 to −0.41, P<0.001), and TSA showed the cumulative sample size reached RIS. In terms of response rate, acupuncture had a higher percentage of at least 50% reduction in headache days compared with sham acupuncture both after treatment (relative risk [RR] 1.28, 95% CI 1.12 to 1.46, P=0.0003) and the follow-up period (RR 1.37, 95% CI 1.19 to 1.58, P<0.0001). The cumulative sample size reached RIS at the follow-up period .Interpretation: Acupuncture is an efficacious treatment for reducing TTH frequency when compared with sham acupuncture or no acupuncture, and TSA showed sufficient statistical power for the evidence. Funding: Sichuan Youth Science and Technology Innovation Research Team (No.2021JDTD0007); National Natural Science Foundation of China (No. 82105026); China Postdoctoral Science Foundation (No. 270461). Declaration of Interest: The authors have no conflicts of interest to declare.