A Cochrane review ¹ included 22 RCTs with a total of 4985 patients with migraine. The number of treatment sessions was between 6 and 12 in 13 trials, and 16 or more in 9 trials. The acupuncture interventions tested in the included trials varied to a great extent. Control groups consisted of no-acupuncture control group (5 trials), a sham-acupuncture control group (15 trials) and a comparator group receiving prophylactic drug treatment (different drugs in all 5 trials).

• Comparison with no acupuncture: Acupuncture was associated with a moderate reduction of headache frequency over no acupuncture after treatment (SMD -0.56, 95% CI -0.65 to -0.48; 4 trials, n=2199). After treatment headache frequency at least halved in 41% of patients receiving acupuncture and 17% receiving no acupuncture (RR 2.40, 95% CI 2.08 to 2.76; 4 studies, n=2519) with a corresponding NNT for an additional beneficial outcome (NNTB) of 4 (95% CI 3 to 6). The only trial (n=377) with post-treatment follow-up found a small but significant benefit 12 months after randomisation (RR 2.16, 95% CI 1.35 to 3.45; NNT 7; 95% 4 to 25).
• Comparison with sham acupuncture: Both after treatment (12 trials, n=1646) and at follow-up (10 trials, n=1534), acupuncture was associated with a small but statistically significant frequency reduction over sham. The SMD was -0.18 (95% CI -0.28 to -0.08) after treatment and -0.19 (95% CI -0.30 to -0.09) at follow-up. After treatment headache frequency at least halved in 50% of participants receiving true acupuncture and 41% receiving sham acupuncture (pooled RR 1.23, 95% CI 1.11 to 1.36; 14 trials, n= 1825) and at follow-up in 53% and 42%, respectively (pooled RR 1.25, 95% CI 1.13 to 1.39; 11 trials, n=1683). The corresponding NNTBs are 11 (95% CI 7.00 to 20.00) and 10 (95% CI 6.00 to 18.00), respectively. The number of participants dropping out due to adverse effects (OR 2.84, 95% CI 0.43 to 18.71; 7 trials, n=931) and the number of participants reporting adverse effects (OR 1.15, 95% CI 0.85 to 1.56; 4 trials, n=1414) did not differ significantly between acupuncture and sham groups.
• Comparison with prophylactic drug treatment: Acupuncture reduced migraine frequency significantly more than drug prophylaxis after treatment (SMD -0.25, 95% CI -0.39 to -0.10; 3 trials, n=739), but the significance was not maintained at follow-up (SMD -0.13, 95% CI -0.28 to 0.01; 3 trials, n=744). After 3 months headache frequency at least halved in 57% of participants receiving acupuncture and 46% receiving prophylactic drugs (pooled RR 1.24, 95% CI 1.08 to 1.44) and after 6 months in 59% and 54%, respectively (pooled RR 1.11; 95% CI 0.97 to 1.26). Trial participants receiving acupuncture were less likely to drop out due to adverse effects (OR 0.27, 95% CI 0.08 to 0.86; 4 trials, n=451) and to report adverse effects (OR 0.25, 95% CI 0.10 to 0.62; 5 trials, n= 931) than participants receiving prophylactic drugs.

Comment: The quality of evidence is downgraded by inconsistency (heterogeneity in interventions).