Acupuncture for migraine without aura: a systematic review and meta-analysis

Migraine without aura (MWoA), the most common type of migraine, has great impacts on quality of life for migraineurs. Acupuncture is used in the treatment and prevention of migraine for its analgesic effects.The aim of this systematic review and meta-analysis is to systematically assess the therapeutic and preventive effect of acupuncture treatment and its safety for MWoA.Nine electronic databases (PubMed, MEDLINE, Cochrane Library, Lilacs, Embase, China National Knowledge Infrastructure (CNKI), Chongqing VIP (CQVIP), Wanfang Data and Chinese Clinical Trial Registry (ChiCTR)) were systematically searched from their beginning through June 2017 using MeSH terms such as "acupuncture, acupuncture therapy, electro-acupuncture, ear acupuncture, acupuncture points, acupuncture analgesia," and "migraine disorders, cluster headache." Manual searching included other conference abstracts and reference lists.Randomized controlled trials (RCTs) with a clinical diagnosis of MWoA, which were treated with acupuncture versus oral medication or sham acupuncture treatment.Two evaluators screened and collected literature independently; they extracted information on participants, study design, interventions, follow-up, withdrawal and adverse events and assessed risk of bias and quality of the acupuncture intervention. The primary outcomes were frequency of migraine (FM) and number of migraine days (NM). Secondary outcomes included the visual analogue scale (VAS) score, effective rate (ER) and adverse events. Pooled estimates were calculated as mean difference (MD) with 95% confidence interval (CI) for continuous data and relative risk (RR) with 95% CI for dichotomous data.Overall, 14 RCTs including 1155 participants were identified. The analysis found that acupuncture had a significant advantage over medication in reducing FM (MD = -1.50; 95% CI: -2.32 to -0.68; P < 0.001) and VAS score (MD = 0.97; 95% CI: 0.63-1.31; P < 0.00001) and had a higher ER (RR = 1.30; 95% CI: 1.16-1.45; P < 0.00001). Acupuncture also had a significant advantage over sham acupuncture in the decrease of FM (MD = -1.05; 95% CI: -1.75 to -0.34; P = 0.004) and VAS score (MD = -1.19; 95% CI: -1.75 to -0.63; P < 0.0001). Meanwhile, acupuncture was more tolerated than medication because of less side effect reports (RR = 0.29; 95% CI: 0.17-0.51; P < 0.0001). However, the quality of evidence in the included studies was mainly low (to very low), making confidence in the FM and VAS score results low.Our meta-analysis shows that the effectiveness of acupuncture is still uncertain, but it might be relatively safer than medication therapy in the treatment and prophylaxis of MWoA. Further proof is needed.