Abstracts

Rationale: Epilepsy carries a risk of premature death that is two to three times higher that the general population. The level of increased mortality is affected by several factors. Sudden Death in Epilepsy (SUDEP) has been identified as the most common cause of death in this population, followed by neoplasms. Contrary to epilepsy, no studies have looked at the causes of death in patients with psychogenic non-epileptic seizures (PNES). We aim to characterize the causes of death in patients with epilepsy and psychogenic non-epileptic seizures. We also assess the possible significant factors associated with SUDEP. Methods: We retrospectively reviewed 3,842 patients admitted to the adult epilepsy-monitoring unit at our institution between 1990 and 2005. The collected data included: demographic variables, neuroimaging, type of epilepsy and pathology. Deaths were identified through social security death index query. The strength of the association was assessed by means of t-test and odds ratio. Results: From the 3,842 patients identified during this period, 307 deaths were captured based on the Social Security Death Index database. The cause of death was identified in 210 through reviews of the death certificates, medical records, and family contact. 79.8% (n=245) of the deaths had epilepsy whereas 20.2% (n=62) had PNES. In the epilepsy cohort, 83.4% had focal epilepsy, the mean age was 47.7 (SD=17.6), the mean seizure frequency per month was 60.6 (SD=139) and the mean monthly generalized tonic-clonic seizure-frequency was 5.42 (SD=14.8). In this cohort, 37 (15.1%) had previous history of clusters, 30 (12.2%) of falls and 17 (6.9%) of status epilepticus. The most common cause of death was SUDEP (22.5%) followed by neoplasms (22%) with half being extra-CNS tumors. Suicide counted for 4.8% of the total deaths. We found a significant association between epilepsy duration (>10 years) and SUDEP (Odds: 3.22; 95%CI: 1.34-7.74. p< 0,006). In the subgroup with SUDEP, patients with more than 5 seizures per month (t= 4.94, p <0.0001), and patients with generalized epilepsy (t=2.9;p 0.0042) died at an earlier age. With regards to the PNES cohort, the mean age of death was 55.9 years (SD=17.8). In this cohort, the most common cause of death was cardiopulmonary failure in 28.8% followed by neoplasms in 26% of the patients. Similar to the epilepsy cohort, suicide counted for 4.4% of the patients. Conclusions: This study provides a unique perspective on mortality in concurrent historical cohorts of epilepsy and PNES. We highlight SUDEP and neoplasms (particularly extra-CNS neoplasms) as the major causes of death, and reinforce the correlation between longer epilepsy duration and a higher risk of SUDEP.