Abstracts

Rationale: Sudden unexpected death in epilepsy (SUDEP) is the leading cause of seizure related death and occurs with an estimated frequency of 1:1,000 general epilepsy patients and 1:250 refractory epilepsy patients. Known risk factors for SUDEP include uncontrolled generalized tonic-clonic seizures (GTCS), nocturnal seizures and developmental delay. Previous SUDEP studies have focused on large epilepsy populations with short-term follow-up and limited characterization of the frequency and severity of seizures.. We sought to understand the long-term characteristics of SUDEP patients, particularly regarding the terminal change in seizure frequency over time. Methods: Deceased patients were identified by query of a longitudinally maintained database of seizure frequency for 2934 epilepsy patients at the University of Virginia. This was cross-referenced to the hospital records. Standard definitions for SUDEP were used. Determination of SUDEP was made based upon chart review and information available in the database, often with information from eye witness reports. Seizure frequency during the last 1, 5 and 10 years of life was analyzed. Other potential risk factors including medication management, presence of GTCS and nocturnal seizures were compared to age and epilepsy syndrome matched controls, using 2 controls per case. Results: 22 SUDEP cases were identified from a total of 181 deaths. The average duration of follow-up was 7.6 years (range 1-17) which constituted 174 patient-years of follow-up, representing an average of 33% of the entire course of the patients’ epilepsy. The mean age of epilepsy onset was 10.1±8.8 years and mean age at death 32.0 years (range 10-53). During the last year of life 20 patients had uncontrolled seizures and 2 patients had > 24 months of seizure freedom. Of the 20 patients that continued to have seizures there was no consistent trend towards worsening seizure frequency in the last year of life as compared to seizure frequencies at 5 and 10 years prior to death, SUDEP patients were more likely than controls to have GTCS (OR 4.70, 95% CI 1.24,17.8) , greater total number of AEDs ever taken (OR 3.12, 95% CI 1.11, 8.73), but not number of AED at last visit (OR 2.19, 95% CI 0.78, 6.07) or sleep as a precipitant (OR 1.28, 95% CI 0.34, 4.77). Conclusions: This represents the first description to our knowledge of the long-term characteristics of epilepsy in SUDEP patients. Worsening seizure frequency was not an obligate risk factor for SUDEP in this sample. The nature and severity of epilepsy in patients that succumbed to SUDEP is heterogeneous, not isolated to super-refractory populations, and not associated with a consistent worsening in seizure frequency. SUDEP patients were statistically more likely to have a history of GTCS and took more AEDs but not be on more AEDs at time of death. Further investigation using case-controls to determine the significance of longitudinal seizure exposure for SUDEP is ongoing. Funding: There was no funding received in support of this abstract.