Does the outcome of acupuncture differ according to the location of sham needling points in acupuncture trials for migraine? A systematic review and network meta-analysis

Various acupuncture clinical trials have been conducted on migraine; however, the conclusions remain controversial especially when acupuncture was compared with sham acupuncture. Sham acupuncture is sometimes performed at the same acupuncture points used for verum acupuncture despite the evidence on acupuncture point specificity. Four databases were searched for sham acupuncture or waiting list-controlled acupuncture trials for migraine on December 25, 2023. Sham acupuncture was classified according to the needling points: sham acupuncture therapy at verum points (SATV) or at sham points (SATS). Network meta-analysis was performed based on the frequentist framework for headache pain intensity and response rate. A total of 18 studies involving 1936 participants were analyzed. Headache pain intensity and response rate were significantly improved in verum acupuncture compared with SATS. However, there was no significant difference between SATV and verum acupuncture. When comparing SATS and SATV, there was no significant difference in headache pain intensity and response rate; however, the results were in favor of SATV. The effect of the risk of bias on the certainty of evidence between verum and sham acupunctures was judged to be generally low. SATV should not be misused as a placebo control to evaluate the efficacy of acupuncture.