Early efficacy and late gain in chronic and high-frequency episodic migraine with onabotulinumtoxinA.

BACKGROUND AND PURPOSE: The aim was to analyse the clinical characteristics of a long-term follow-up of patients with chronic and high-frequency episodic migraine in treatment with onabotulinumtoxinA.

METHODS: Patients diagnosed with high-frequency episodic migraine (HFEM) or chronic migraine (CM) according to the International Classification of Headache Disorders 3 beta were included. A comparative analysis was carried out at each study time point identifying outcome measures according to initial diagnosis and treatment duration.

RESULTS: In all, 578 patients were recruited and after 24 months outcome data were collected from 100 patients: 84.0% CM and 16.0% HFEM. After 24 months, headache frequency was significantly reduced by 10.5 days from baseline, 64.0% reported a ≥50% reduction in pain intensity and 70.0% of patients had ≥50% reduction in analgesic use. Comparing baseline diagnoses, at month 6 CM patients presented higher mean reduction in frequency (CM 44.3% ± 32.6% vs. HFEM 34.6% ± 24.8%) and analgesic use (CM 53.6% ± 35.4% vs. HFEM 39.3% ± 33.2%). At month 12, the mean reduction in frequency was similar in CM and HFEM patients (CM 44.7% ± 33.4% vs. HFEM 41.2% ± 28.2%). Improvement in pain intensity, analgesic use and Migraine Disability Assessment were proportional in both diagnoses.

CONCLUSIONS: OnabotulinumtoxinA efficacy is significant at 6 months in frequency and analgesic intake and remains stable during follow-up, whilst the intensity of pain decreases in a stepwise manner at each time point of the analysis. The improvement in CM and HFEM patients is proportional and significant after 1 year of treatment.