Long-Term Mortality in Childhood-Onset Epilepsy.

Background: There are few studies on long-term mortality in prospectively followed, well-characterized cohorts of children with epilepsy. We report on long-term mortality in a Finnish cohort of subjects with a diagnosis of epilepsy in childhood. Methods: We assessed seizure outcomes and mortality in a population-based cohort of 245 children with a diagnosis of epilepsy in 1964; this cohort was prospectively followed for 40 years. Rates of sudden, unexplained death were estimated. The very high autopsy rate in the cohort allowed for a specific diagnosis in almost all subjects. Results: Sixty subjects died (24%); this rate is three times as high as the expected age- and sex-adjusted mortality in the general population. The subjects who died included 51 of 107 subjects (48%) who were not in 5-year terminal remission (i.e., greater/equal 5 years seizure-free at the time of death or last follow-up). A remote symptomatic cause of epilepsy (i.e., a major neurologic impairment or insult) was also associated with an increased risk of death as compared with an idiopathic or cryptogenic cause (37% vs. 12%, P<0.001). Of the 60 deaths, 33 (55%) were related to epilepsy, including sudden, unexplained death in 18 subjects (30%), definite or probable seizure in 9 (15%), and accidental drowning in 6 (10%). The deaths that were not related to epilepsy occurred primarily in subjects with remote symptomatic epilepsy. The cumulative risk of sudden, unexplained death was 7% at 40 years overall and 12% in an analysis that was limited to subjects who were not in long-term remission and not receiving medication. Among subjects with idiopathic or cryptogenic epilepsy, there were no sudden, unexplained deaths in subjects younger than 14 years of age. Conclusions: Childhood-onset epilepsy was associated with a substantial risk of epilepsy-related death, including sudden, unexplained death. The risk was especially high among children who were not in remission. (Funded by the Finnish Epilepsy Research Foundation.) N Engl J Med 2010;363:2522-9.