Long-term survival after adult epilepsy surgery: Mortality and predictors in a large cohort.

Objective: Long-term survival data in adults undergoing surgery for drug-resistant focal epilepsy remain limited. We examined mortality patterns and predictors in a large cohort followed for over 30 years.

Methods: Adults who underwent epilepsy surgery (1990-2022) were analyzed. Prospectively collected clinical, surgical, and outcome data were included. We estimated the cumulative incidence of mortality and standardized mortality ratios (SMRs) for the cohort. Predictors of epilepsy-related and non-epilepsy-related deaths were identified using Fine-Gray and cause-specific hazard models.

Results: A total of 1062 individuals contributed 14 279 person-years of follow-up (median, 13 years). The overall mortality rate was 6.16 per 1000 person-years, with 2.52 per 1000 person-years due to epilepsy-related deaths, including 0.84 per 1000 person-years from sudden unexpected death in epilepsy (SUDEP). Epilepsy-related deaths were more frequent within the first 15 years post-surgery (p = 0.006). The overall SMR was 1.12 (95% confidence interval [CI]: 0.90-1.38), and 0.65 (95% CI: 0.46-0.89) among individuals followed for more than 15 years. Independent predictors of epilepsy-related mortality were older age at surgery, cortical malformations, and poor post-operative seizure control (International League Against Epilepsy [ILAE] outcome class ≥4). Non-epilepsy-related mortality was driven primarily by older age at surgery.

Significance: Epilepsy surgery is associated with reduced premature mortality and increasingly normalized long-term survival. Age at surgery, post-operative seizure control, and pathological findings are key determinants of survival, highlighting opportunities to improve surgical outcomes further.