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

TLDR

The study aimed to determine the prevalence of epilepsy and the frequency and characteristics of pharmacoresistant epilepsy in adults. Researchers identified all adults with epilepsy in a French city, defined pharmacoresistance as failure of at least two first‑line antiepileptic drugs with ≥1 seizure per month for 18 months, and had experts review records and patients using a standardized questionnaire and ILAE criteria. The age‑adjusted prevalence of active epilepsy was 5.4 per 1,000 (higher in males), 15.6 % of cases were pharmacoresistant (0.94 per 1,000), and roughly one in eight patients had uncontrolled epilepsy.

Abstract

To determine the prevalence of epilepsy in a defined adult population and identify the frequency and principal features of pharmacoresistant epilepsy.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.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).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.