Factors associated with long‐term outcomes in people with new onset refractory epilepticus: A single‐center cohort study

Abstract Objective New onset refractory status epilepticus (NORSE) is a neurologic emergency in people without a history of active epilepsy or other preexisting neurological disorders. There are not many studies reporting on the long‐term outcomes of NORSE. We investigate factors associated with outcomes such as mortality and sequelae in NORSE. Methods This retrospective, single‐center study involved individuals diagnosed with NORSE in West China hospital who were consecutively admitted between January 2018 and December 2022. The primary outcome was death at follow‐up. Secondary outcomes included functional recovery and sequelae among survivors. Lasso–Cox regression was used to evaluate factors for death. A Cox proportional hazard regression model was then established, incorporating several parameters identified through Lasso–Cox regression. Results One hundred one individuals with NORSE were identified and reviewed (median age = 30 years, 45 (45%) were female). The etiology was unknown in 37 (37%) people despite comprehensive diagnostic workups. Among the remaining 64 (64%), the most common etiology of NORSE was autoimmune encephalitis ( n = 53, 83%), followed by infectious encephalitis ( n = 9, 14%). One person died in‐hospital, and 24 (24%) died during follow‐up. Factors independently associated with death were the presence of superrefractory status epilepticus (hazard ratio [HR] = 3.99, 95% confidence interval [CI] = 1.09–14.61, p = .036) and initial response to immunotherapy (HR = .11, 95% CI = .02–.62, p = .012). The median follow‐up duration among the 76 survivors was 40 months (range = 24–82 months). Among them, functional recovery was achieved in 52 (68%) at the last follow‐up, whereas sequelae were seen in 24 people, the most common being active epilepsy ( n = 9, 12%). Significance The primary etiology in the NORSE cohort was autoimmune, followed by unknown causes. Response to immunotherapy is highly associated with long‐term mortality, even in those with unknown etiology.