Abstracts

RATIONALE: To perform a meta-analysis of the reported rates of sudden unexplained death in epilepsy (SUDEP) in epilepsy treatment trials. SUDEP rates vary depending on the population studied ranging from 0.35 per 1000 person years in the general epilepsy population (Ficker et al, Neurology 1999) to 9.3 per 1000 person years in an epilepsy surgery cohort (Dasheiff, J Clin Neurophysiol 1991). The SUDEP rate in a tertiary epilepsy center is 5.9 per 1000 person years (Nashef et al, J Neurol Neurosurg Psychiatry 1995) Many of the newer antiepileptic medications have reported SUDEP rates as part of their clinical development. METHODS: SUDEP rates were obtained from the product information for the following: gabapentin, lamotrigine, topiramate, tiagabine, zonisamide and the vagus nerve stimulator. SUDEP rates were not available for felbamate, levetiracetam, or oxcarbazepine. A meta-analysis of the SUDEP rates was performed. The mean SUDEP rate was estimated by over-dispersed Poisson regression using the GENMOD procedure in SAS. RESULTS: SUDEP rates range from 2.6 to 7.7 per 1000 person years. The estimated mean SUDEP rate is 3.79 per 1000 person years, with 95% confidence intervals (2.88, 4.88). CONCLUSIONS: The estimated SUDEP rate of 3.79 per 1000 person years compares to the rate found in epilepsy referral centers, but is greater than in the general epilepsy population. Patients enrolled in clinical trials typically have poorly controlled epilepsy compared to the general epilepsy population. The meta-analysis results suggest that refractory epilepsy is a risk factor for SUDEP.