The effects of adjunctive topiramate therapy on seizure severity and health-related quality of life in patients with refractory epilepsy---a Canadian study

Abstract

Although reduction in seizure frequency is the most common endpoint used to assess the antiepileptic efficacy, seizure frequency alone does not provide a complete picture of effectiveness, particularly in patients with refractory epilepsy. The aim of our study was to assess the effects of topiramate on seizure severity and health-related quality of life (HRQL), in addition to standard efficacy measures, in an open, multicentre, 6-month trial of patients with epilepsy uncontrolled on antiepileptic drugs other than topiramate. Two hundred and nine patients were enrolled and received topiramate for up to 6 months (initiated at 50 mg/day and titrated to a recommended dose of 200-400 mg/day) in addition to existing medication. The median reduction in seizure frequency from baseline to the post-titration period was 40.9% ( P< 0.0001). Patients also demonstrated a mean reduction in the Liverpool Seizure Severity Scale (LSSS) of 5.3 ( P< 0.0001), which was considered clinically significant. Statistically significant changes in HRQL were not observed with the SF-36, a generic measure. Tolerability of antiepileptic medication was good, with a low incidence of cognitive adverse events. The results indicate that topiramate significantly reduces seizure severity---an important aspect of HRQL---when administered as adjunctive therapy to anticonvulsant therapy.