title: Factors associated with the prophylactic effect of placebo injections in subjects enrolled in a study of botulinum toxin for migraine.
abstract: We set out to identify predictors for the prophylactic effect of placebo injections in subjects with migraine by post hoc analysis of 81 subjects with episodic migraine receiving single-blind placebo injections in a prospective trial of botulinum toxin. Possible predictors of placebo prophylaxis were compared among placebo responders (PRs) and placebo non-responders (PNRs). There were 34 PRs (42%) and 47 PNRs (58%). Male gender [odds ratio (OR) 5.83, 95% confidence interval (CI) 1.12, 30.14, P = 0.022], a history of opioid use (OR 4.44, 95% CI 1.47, 13.41, P = 0.005) and injections in the neck/shoulders (OR 2.44, 95% CI 0.93, 3.19, P = 0.033) were associated with placebo response. Of subjects with two or more of these signs, 88% were PRs compared with 31% of subjects with one or less. Male gender, opioid use and injections in the neck/shoulders are associated with placebo prophylaxis. These findings may have important implications for the design of future clinical trials and for the clinical management of migraineurs.
authors: Department of Neurology, Mayo Clinic College of Medicine, Scottsdale, AZ 85259, USA.
authors: T J
authors: TJ
authors: Schwedt
authors: J G
authors: JG
authors: Hentz
authors: D W
authors: DW
authors: Dodick
mesh_terms: D000328:Adult; D000701:Analgesics, Opioid / Q000494:pharmacology; D019274:Botulinum Toxins, Type A / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008881:Migraine Disorders / Q000517:prevention & control*; D009465:Neuromuscular Agents / Q000627:therapeutic use*; D015990:Placebo Effect; D012737:Sex Factors
chemical_list: D000701:Analgesics, Opioid; D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A