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

Migraine is a common neurological disease with a significant global prevalence and socioeconomic burden. Acupuncture, a nonpharmacologic intervention, has been widely used for its treatment due to its effectiveness and safety. However, the controversy surrounding the use of sham acupuncture as a control in clinical trials has led to inconsistent conclusions about the effectiveness of acupuncture. This systematic review and network meta-analysis aimed to investigate whether the outcome of acupuncture for migraine is affected by sham intervention at the same acupuncture points as those in verum acupuncture or at non-indicated sham points.

The review included randomized controlled clinical trials involving adults diagnosed with migraine. Interventions included verum acupuncture, sham acupuncture, and waiting list (no treatment). Verum acupuncture was defined as manual acupuncture penetrating the skin without additional stimulation. Sham acupuncture was classified into two groups: sham acupuncture therapy at verum acupuncture points (SATV) and sham acupuncture therapy at sham points (SATS). The primary outcome was headache pain intensity, and secondary outcomes included response rate and frequency of migraine attacks.

A comprehensive search of multiple databases was conducted to identify eligible studies. After screening, 18 studies involving 1936 participants were included in the analysis. The countries where the studies were conducted varied, including China, Germany, Iran, Australia, Canada, Sweden, Brazil, and Italy. The studies were published between 2005 and 2023, and most compared verum acupuncture with sham acupuncture.

The risk of bias assessment using the Cochrane risk of bias tool revealed that most studies adequately generated random sequences and concealed allocation. However, some studies had an unclear or high risk of bias in certain domains. The network meta-analysis showed that both verum acupuncture and sham acupuncture significantly reduced headache pain intensity and improved response rates compared with the waiting list. When comparing SATS and SATV with verum acupuncture, verum acupuncture significantly improved pain intensity and response rate compared with SATS, but there was no significant difference between SATV and verum acupuncture. The analysis also indicated potential publication bias for headache pain intensity and a high or moderate certainty of evidence for the estimates.

In conclusion, the outcome of acupuncture for migraine differed based on the location of sham needling points. SATV did not significantly differ from verum acupuncture, suggesting that sham acupuncture methods should be carefully established according to the research hypothesis. This study highlights the importance of considering the specific needling points in sham acupuncture when designing and interpreting acupuncture clinical trials for migraine. Future research should focus on improving the reporting quality of sham acupuncture and conducting mechanistic studies to better understand its effects.

DOI: 10.1007/s11684-024-1109-z