Incidence rate of sudden death in epilepsy: A systematic review and meta-analysis

Objective: The aim of the study was to summarize the pooled incidence rate of sudden unexpected death in epilepsy (SUDEP) in patients. Meta-regression analysis was applied to identify factors influencing the incidence rate. Design: The study was a systematic review and critical appraisal with a meta-analysis of cohort studies, both prospective and retrospective. Material and method: In a literature search, a total of 45 cohort studies were identified. A random effect model was used to synthesize the results. Heterogeneity between studies was examined by subgroup and meta-regression analysis. The small-study effect was evaluated and not corrected for by the "trim and fill" method because of great heterogeneity. Results: A substantial heterogeneity was present. The pooled estimated incidence rate for SUDEP was 1.4/1000 patient years. A meta-regression pinpointed a negative association between the incidence rate of SUDEP and the mean follow-up time and a positive association with the mean age of the patient. The definition of epilepsy showed statistical significance, with a higher incidence rate of SUDEP in studies where the definition of epilepsy was described and clear (p = 0.019) compared with studies having an inadequate or failing epilepsy definition. Conclusion: Evidence from this study suggests a high incidence rate of sudden death in epilepsy. Its incidence rate was 23 times the incidence rate of sudden death in the total population of the same age. There was heterogeneity and variability of incidence rate depending on the quality of the study and on the definition of epilepsy and the mean age of the patients. (C) 2018 Elsevier Inc. All rights reserved.