Background and ObjectivesThe outcome of status epilepticus (SE) largely varies depending on clinical characteristics. Risk stratification is necessary for tailoring the aggressiveness of treatment and predicting outcomes of individual patients with SE. In this study, we assessed differences in mortality, neurologic disability, and prognostic factors associated with SE across sociodemographic and clinical characteristics.MethodsWe conducted a nationwide population-based retrospective cohort study using the National Health Insurance Service (NHIS) database linked with the national death and disability registries. SE was identified from admission or emergency department visits using a diagnostic code of G41 from the International Classification of Diseases, 10th Revision. Individuals with new-onset SE that occurred from January 1, 2010, to December 31, 2018, were included. Active epilepsy, refractoriness of SE, potential etiology, and comorbidities were ascertained by diagnostic codes and/or prescription records from the NHIS database as potential prognostic factors. Outcomes included 30-day and 1-year mortality and neurologic disabilities after SE. Prognostic factors for mortality were assessed by the Cox regression hazard model. We performed a subgroup analysis according to age: pediatric SE (age <20 years) and adult SE (age ≥20 years).ResultsA total of 33,814 patients with new-onset SE were included (6,818 children/adolescents and 26,996 adults). The 30-day mortality was 8.5% (1.8% in pediatric SE and 10.2% in adult SE), and the 1-year mortality was 25.1% (4.6% in pediatric SE and 30.3% in adult SE). Overall, 10.7% of patients newly acquired neurologic disabilities after SE, with the highest incidence in children aged 5-9 years (21.3%). Intractable epilepsy developed in 0.8% of entire SE. Old age, presence of acute etiology, and refractoriness were poor prognostic factors for mortality in both pediatric and adult SE. Male sex, low economic status, no active epilepsy, and comorbidities were additional factors for a poor prognosis in adults.DiscussionNew-onset SE was associated with substantial mortality and disability. Although SE-related mortality was higher in adults, disabilities developed more commonly in children and adolescents. The major determinants of mortality differed between pediatric and adult SE.