Sudden unexpected death in epilepsy. A nationwide population-based study

The incidence of sudden unexpected death in epilepsy (SUDEP) varies between studies. We determined the incidence of SUDEP in the entire Icelandic population during a 20-year period.

All individuals in Iceland with epilepsy who died unexpectedly from January 1, 1991 through December 31, 2010 were included. Case ascertainment was based on autopsies, reimbursement for antiepileptic drugs, death certificates, information from neurologists, and medical records. The incidence of SUDEP was calculated according to the total number of residents in Iceland during the study period and an estimated epilepsy population of Iceland.

We identified 37 individuals (26 men, 11 women) with definite SUDEP (n = 29), definite SUDEP plus (n = 4), and probable SUDEP (n = 4). Incidence of SUDEP was 0.6 per 100 000 person-years for the general population, and higher among men. The estimated incidence of SUDEP in the epilepsy population was 1.3 per 1000 person-years. SUDEP accounted for 0.1% of all deaths in Iceland during the study period.

SUDEP is an important cause of death in working-age people. This study provides the incidence of SUDEP in an unselected population of an entire country. The SUDEP incidence in the epilepsy population is comparable to that of previous studies.