Evaluation of health status in epilepsy using the EQ-5D questionnaire: a prospective, observational, 6-month study of adjunctive therapy with anti-epileptic drugs

Aims: The aims of this project were to evaluate the impact of adjunctive treatment with an anti-epileptic drug (AED) on the health status of people with epilepsy and to investigate how seizure frequency affects their health status. Methods: Adult epilepsy patients, refractory to current treatment, were included in this prospective observational study. Patients commencing adjunctive therapy with one of five AEDs (topiramate, lamotrigine, gabapentin, clobazam, vigabatrin) were eligible for inclusion. The study took place at the outpatient clinics of the National Hospital for Neurology and Neurosurgery, Queen Square, London. Patients completed the EQ-5D, a generic health status measure, at baseline and again after 3 and 6 months. Information was also collected on medications and seizure frequency. Results: In total, 125 patients entered the study and were followed up for 6 months. Patients treated with topiramate had a significant increase (p < 0.05) in EQ-5D score from baseline, indicating an improvement in their health status whereas scores for lamotrigine, clobazam and gabapentin all showed a non-significant decline. When the data were analysed according to seizure frequency, only patients who became seizurefree on adjunctive treatment had a significant increase in their health status. The group who had a 50% reduction in seizure frequency did not have increased health status. Conclusions: In summary, adjunctive treatment with topiramate significantly increased health status as measured by the EQ-5D. These data also suggest that achievement of seizure-freedom is the key to improving health status in this patient group.