Botulinum Toxins for the Prevention of Migraine in Adults

Summary

A Cochrane review [Abstract] 1 included 28 studies with a total of 4190 patients. Overall 85% of the patients were women. The longest treatment duration was 3 rounds of injections with 3 months between treatments. The follow-up period ranged from 4 weeks to 9 months. For primary analyses the data are pooled from both chronic and episodic patients. Most trials (21 out of 28) were small (fewer than 50 participants per trial arm). The evidence is not sufficient for investigation of the effect of botulinum toxin on the medication overuse headache subgroup.

• Botulinum toxin vs. placebo: Botulinum toxin reduces the number of migraine days per month in the chronic migraine by 3.1 days (95% CI -4.7 to -1.4; 4 trials, n=1497). This was reduced to -2 days (95% CI -2.8 to -1.1; 2 trials, n=1384), when small trials were removed. A trial with episodic migraine (n = 418) showed no difference between groups (p = 0.49). In the chronic migraine population, botulinum toxin reduces the number of headache days per month by 1.9 days (95% CI -2.7 to -1.0; 2 trials, n=1384). There is no difference in the number of migraine attacks for both chronic and episodic migraine participants (6 trials, n= 2004). For both chronic and episodic migraine patients a reduction in severity of migraine rated during clinical visits, on a visual analogue scale (VAS) of 3.3 (95% CI -4.2 to -2.5) in favour of botulinum toxin treatment came from 4 small trials (n = 209). There is an increase in the RR with treatment with botulinum toxin over placebo of 30% (RR 1.28, 95% CI 1.12 to 1.47).
• Botulinum toxin vs. other prophylactic agent: Meta-analyses were not possible for number of migraine or headache days or number of migraine attacks due to insufficient data, but individually trials reported no differences between groups for a variety of efficacy measures in the population of both chronic and episodic migraine participants. The global impression of disease measured using Migraine Disability Assessment (MIDAS) scores were reported from 2 trials that showed no difference between groups. Compared with oral treatments, botulinum toxin showed no between-group difference in the risk of adverse events (2 trials, n = 114). The relative risk reduction (RRR) for withdrawing from botulinum toxin due to adverse events compared with the alternative prophylactic agent was 72% (p = 0.02, 2 trials, n = 119).