Potential years lost and life expectancy in adults with newly diagnosed epilepsy

Studies using relative measures, such as standardized mortality ratios, have shown that patients with epilepsy have an increased mortality. Reports on more direct and absolute measure such as life expectancy are sparse. We report potential years lost and how life expectancy has changed over 40 years in a cohort of patients with newly diagnosed epilepsy.

We analyzed life expectancy in a cohort of adult patients diagnosed with definite epilepsy between 1970 and 2010. Those with brain tumor as cause of epilepsy were excluded. By retrospective probabilistic record linkage, living or death status was derived from the national death registry. We estimated life expectancy by a Weibull regression model using gender, age at diagnosis, epilepsy etiology, and year of diagnosis as covariates at time of epilepsy diagnosis, and 5, 10, 15, and 20 years after diagnosis. Results were compared to the general population, and 95% confidence intervals are given.

There were 249 deaths (105 women, age at death 19.0-104.0 years) in 1,112 patients (11,978.4 person-years, 474 women, 638 men). A substantial decrease in life expectancy was observed for only a few subgroups, strongly depending on epilepsy etiology and time of diagnosis: time of life lost was highest in patients with symptomatic epilepsy diagnosed between 1970 and 1980; the impact declined with increasing time from diagnosis. Over half of the analyzed subgroups did not differ significantly from the general population. This effect was reversed in the later decades, and life expectancy was prolonged in some subgroups, reaching a maximum in those with newly diagnosed idiopathic and cryptogenic epilepsy between 2001 and 2010.

Life expectancy is reduced in symptomatic epilepsies. However, in other subgroups, a prolonged life expectancy was found, which has not been reported previously. Reasons may be manifold and call for further study.