Factors predicting the probability of relapse after discontinuation of migraine preventive treatment with topiramate.

INTRODUCTION: Demographic and clinical variables were examined in a post hoc analysis of the PROlonged Migraine Prevention with Topiramate (PROMPT) study to determine potential contribution to relapse. METHODS: After a six-month open-label (OL) topiramate phase, patients were randomised to continue topiramate or switch to placebo in a six-month double-blind (DB) phase. 'Relapse' was investigated in terms of change in monthly migraine days after randomisation compared with the month before randomisation, and was analysed during the first ('initial relapse') and last month ('sustained relapse') of the DB phase. More than 40 potential predicting factors were entered into analyses of variance and covariance. RESULTS: For initial relapse, variable-by-treatment interactions were significant for the Headache Impact Test (HIT-6) at DB baseline, and decline in acute medication intake or reporting of 'anxiety' in the OL phase. For sustained relapse, no statistically significant interactions were observed. CONCLUSION: Relapse after topiramate discontinuation in migraine prophylaxis appears to be unaffected by patient characteristics or baseline migraine frequency.