Prognosis of epilepsy: A review and further analysis of the first nine years of the British National General Practice Study of epilepsy, a prospective population-based study

Abstract

Purpose: To understand the prognosis of newly diagnosed epilepsy to provide rational therapy and advice for patients and their physicians. Methods: The National General Practice Study of Epilepsy (NGPSE) is the first large population-based study that has assessed the prognosis of patients with newly diagnosed epilepsy prospectively over a prolonged period. We review the previously published data on the prognosis of epilepsy after 9 years of follow-up. One thousand ninety-one patients with newly diagnosed or suspected epilepsy who were attending 1 of 275 general practices throughout the United Kingdom between 1984 and 1987 were ascertained. Cases in this study were de fined as the occurrence of one or more seizures, including provoked seizures. Prognosis in terms of remission of seizures, and mortality, was analyzed in the patients who were classified 6 months after recruitment as having definite epilepsy (n = 564) or possible/probable epilepsy (n = 228). Results: Only 33 patients were completely lost to follow-up. After 9 years, 86% [95% confidence interval (CI) 81, 90] of patients with definite epilepsy had achieved a remission of 3 years, and 68% (CI 61, 75), had achieved a remission of 5 years. For the complete cohort, with possible/probable epilepsy included, the rates increased to 87% (CI 83, 91) for 3-year remission and 71% (CI 65, 77) for 5-year remission. The proportion of patients with definite epilepsy who were still in remission at 9-year follow- up (terminal remission) was 68% (CI 62, 74) for 3-year remission and 54% (CI 48, 60) for 5-year remission. When stratified by etiology, the proportions achieving 5-year remission by 9 years was 69% (CI 60, 77) for idiopathic seizures, and 61% (CI 46, 75) for remote symptomatic epilepsy. Age and seizure type had small effects on the chances of achieving remission, with children experiencing slightly lower rates than older patients, and partial seizures having lower remission rates than generalized seizures. The overall standardized mortality ratio (SMR) for patients with definite or possible/probable epilepsy was 2.5 (CI 2.1, 2.9), and 3.0 (CI 2.5, 3.7) for patients who were classified as having definite epilepsy. The SMR for patients with idiopathic epilepsy was 1.6 (CI 1.0, 2.4), for those with remote symptomatic epilepsy it was 4.3 (CI 3.3, 5.5), and for those with acute symptomatic epilepsy it was 2.9 (CI 1.7, 4.5). Conclusions: Overall, most patients with epilepsy will enter remission; however, there is a higher than expected risk of death, especially in those with symptomatic epilepsy.