The prevalence of epilepsy and pharmacoresistant epilepsy in adults: A population‐based study in a Western European country

Abstract

Summary: Purpose: To determine the prevalence of epilepsy in a defined adult population and identify the frequency and principal features of pharmacoresistant epilepsy. Methods: From a population over 15 years of age residing in a medium‐sized French city, all patients with epilepsy on June 30, 1995 were identified from multiple sources. Pharmacoresistance was defined as failure to control epilepsy by at least two first‐line antiepileptic drugs, with a seizure frequency of at least one per month for 18 months. Collected data were examined by experts in epileptology, and responding patients were reexamined using a standardized diagnostic questionnaire. ILAE definitions and classifications were used. Results: The age‐adjusted prevalence of active epilepsy was 5.4 per 1,000 (95% CI: 4.7–6.0) and was higher for males (7.8) than for females (5.2). For epilepsy in remission under treatment, this rate was 0.7 per 1,000 (95% CI: 0.5–0.95). Age‐specific prevalence was highest in age groups 25–49 years and declined in the oldest age groups. Localization‐related seizures represented 61.1% of cases and generalized seizures 30.9%. The proportion of noncontrolled epilepsy (seizure‐frequency at least one per month for 18 months) was 15.6%, corresponding to a prevalence of 0.94 per 1,000. In this group, the mean age at onset was lower (p = 0.0007) and localization‐related epilepsy more frequent (p = 0.01). Conclusion: The findings support previous epidemiological estimates of the prevalence of epilepsy in developed countries. For approximately one patient in eight, epilepsy was not adequately controlled.