Short and Mid-Term Predictors of Response to OnabotulinumtoxinA: Real-Life Experience Observational Study

Objective To identify clinical predictors of excellent response to OnabotulinumtoxinA in patients with chronic migraine (CM) at 6 and 12 months of follow-up. Background Clinical predictors of response to OnabotulinumtoxinA are scarce and have not been clearly reproduced and analyzed in detail. So far, predictors of response to OnabotulinumtoxinA assess response in general or good response, but not an excellent response. Methods Cohort study of patients attended in a specialized Headache Clinic in treatment with OnabotulinumtoxinA were classified according to their improvement in frequency: no-response (<25%) and excellent response (>= 75%). A comparative analysis was carried out at 6 and 12 months identifying clinical predictors of excellent response to OnabotulinumtoxinA at each timepoint. Results Data were collected from 221 patients. After 6 and also 12 months, we observed a statistically significant mean reduction in frequency and analgesic intake. At month 6, independent variables associated with excellent response (OR[95%CI]) were daily headache frequency (0.32[0.14-0.74]; P = .005), medication overuse (MO) (2.28[1.19-4.37]; P = .013), and a higher ratio of migraine days/month (MDM) (1.20[1.10-1.45]; P = .018) at baseline. At month 12, independent predictors of excellent response were patients with less than 30 years of migraine evolution (0.43[0.23-0.82]; P = .011), presence of anxiety (0.44[0.23-0.85]; P = .018), and aura (0.48[0.25-0.92]; P = .037). Excellent responders showed a higher improvement rate in pain intensity at 6 and 12 months. Conclusions Patients with daily frequency and MO show a clinical improvement in short-term. Patients with comorbidities who start treatment earlier in the course of the disease need a longer duration of treatment. The profile of response to treatment with OnabotulinumtoxinA determines its minimum treatment duration and the timepoint of a meaningful response.