Incidence of first-episode status epilepticus and risk factors in Ontario, Canada

Background Status epilepticus (SE) is a neurological emergency characterized by prolonged seizures. However, the incidence of first-episode SE is unclear, as estimates vary greatly among studies. Additionally, SE risk factors have been insufficiently explored. Therefore, the objectives of this study were to estimate the incidence of first-episode SE in Ontario, Canada, and estimate the associations between potential sociodemographic and health-related risk factors and first-episode SE. Methods We conducted a population-based retrospective cohort study using linked health administrative datasets. We included individuals who completed Canada s 2006 Census long-form questionnaire, lived in Ontario, were between 18 and 105, and had no history of SE. A Cox proportional hazards regression model was used to estimate the hazard ratios for SE within three years associated with each potential risk factor. Results The final sample included 1,301,700 participants, 140 of whom were hospitalized or had an emergency department visit for first-episode SE during follow-up (3.5 per 100,000 person42 years). Older age was the only significant sociodemographic SE risk factor (HR=1.35, 95% CI=1.33, 1.37), while health-related risk factors included alcohol or drug abuse (HR=1.05, 95% CI=1.02, 1.08), brain tumour or cancer (HR=1.14, 95% CI=1.12, 1.15), chronic kidney disease (HR=1.32, 95% CI=1.29, 1.36), dementia (HR=1.42, 95% CI=1.36, 1.48), diabetes (HR=1.11, 95% CI=1.09, 1.12), epilepsy or seizures (HR=1.05, 95% CI=1.01, 1.09), and stroke (HR=1.08, 95% CI=1.05, 1.11). Conclusion The estimated incidence of SE in a sample of Ontario residents was 3.5 per 100,000 person50 years. Older age and several comorbid conditions were associated with higher first-episode SE risk.