Are comorbid sleep disorders associated with higher risk for sudden unexpected death in epilepsy? Observations from a...

Pooled mortality is nearly three times higher in people with epilepsy (PWE). Approximately 80% of sudden unexpected death in epilepsy (SUDEP) events occur during sleep, and primary sleep disorders are prevalent in the general population and PWE. Currently, research extensively explores SUDEP risk and biomarkers, whereas limited studies investigate the connection between sleep and SUDEP/all-cause mortality risk in epilepsy. This study assessed the relationship between SUDEP risk in epilepsy and primary sleep disorder diagnoses.

This retrospective chart review included consecutive patients with active epilepsy from a Canadian epilepsy clinic over a 4-year period. The database included demographic, clinical, neurophysiological, sleep information, accident, and hospitalization records. The revised SUDEP-7 Inventory (rSUDEP-7) evaluated SUDEP risk, and sleep disorder diagnoses were accepted if evaluated by a sleep specialist based on International Classification of Sleep Disorders version 3.0 criteria. Patients were categorized into those without comorbid sleep disorders (NoSleepDis) and those with sleep disorders (SleepDis), and sociodemographic and clinical characteristics were compared. The association between sleep disorders and SUDEP risk was assessed using logistic and ordinal logistic regression models.

The study enrolled 1506 PWE (1130 in NoSleepDis, 376 in SleepDis). The groups were similar in age, sex, living situation, epilepsy duration, epilepsy type, and percentage seizure-free for >1 year. Univariately, the SleepDis group exhibited a significantly higher SUDEP risk, as well as higher all-cause mortality and accidents, but not hospitalizations. Sleep disorder presence was associated with increased odds of high SUDEP risk (rSUDEP-7 ≥ 5, odds ratio [OR] = 1.93, 95% confidence interval [CI] = 1.02-3.64) and higher SUDEP-7 scores when analyzed ordinally (OR = 1.46, 95% CI = 1.17-1.81).

Comorbid primary sleep disorders among PWE are associated with higher SUDEP risk (rSUDEP-7 scores), all-cause mortality, and accident rates. This study offers insights for developing more accurate predictive tools for assessing SUDEP risk for epilepsy.