Epidemiology of sudden unexpected death in epilepsy (SUDEP)

The incidence of SUDEP ("sudden unexpected death in epilepsy") is about 1/1000 person-years in population-based studies in developed countries. The incidence is lower in patients in remission or newly diagnosed epilepsy, but considerably higher (to about 10/1000 person-years) in patients included in studies with new antiepileptic drugs (AED) or VNS studies, candidates for epilepsy surgery, and patients with mental retardation. The risk of SUDEP is lower in children than in adults with epilepsy. Compared to normal population the risk for a sudden, unexplained death is about 20-40x higher. Based on an estimated incidence of 1/1000 person-years about 500 SUDEP per year are expected in Germany. However, reliable data about incidence of SUDEP in Germany is missing. Different risk factors/predictors for SUDEP (e.g. seizure frequency, number of AED, certain AED, non-compliance, co-morbidity) were investigated. The results are in part contradictory, but seizure frequency seems to be a crucial factor. Various potential pathomechanisms comprise (e.g. cardiac arrhythmia or central apnoea) are discussed. In most cases SUDEP appears seizure-related, especially in association with generalized tonic-clonic seizures. Thus control of seizures seems of major importance in preventing SUDEP. Many questions in regard to mortality and SUDEP are still open and further research is required.