Predicting epilepsy after new onset refractory status epilepticus due to autoimmune encephalitis: The DAME score

Objective: This study aimed to identify risk factors and develop a predictive scoring system for autoimmune-associated epilepsy in subjects with autoimmune encephalitis presenting with new onset refractory status epilepticus (NORSE). Methods: This retrospective, multicenter, cohort study included subjects who presented with NORSE at the onset of autoimmune encephalitis and had at least 24 months of follow-up after immunotherapy. The outcome was the development of autoimmune-associated epilepsy, defined as persistent seizures despite adequate immunotherapy and absence of active inflammation. Factors independently associated with the outcome were identified through a backward stepwise selection. Adjusted regression coefficients of each independent predictor were transformed to produce a points-based risk-scoring system. Results: Seventy participants were included (median age = 24.2 years, 38.6% male). During a median follow-up of 53 months, 54.3% of subjects developed autoimmune-associated epilepsy. Status epilepticus duration ≥ 10 days (odds ratio [OR] = 31.14, 95% confidence interval [CI] = 2.12-456.87, p = .012), positivity for antibodies against surface antigens (OR = .12, 95% CI = .02-.85, p = .034), bitemporal magnetic resonance imaging (MRI) abnormalities suggestive of autoimmune encephalitis during acute stage (OR = 49.80, 95% CI = 2.95-841.77, p = .007), and interictal epileptiform discharges during electroencephalographic (EEG) follow-up (OR = 71.32, 95% CI = 6.48-785.32, p < .001) were independently associated with the study outcome. The duration-antibodies-MRI-EEG (DAME) score was developed as an integer-based scoring system predictive of autoimmune-associated epilepsy. With an optimal cutoff of ≥3 points, it yielded a sensitivity of 86.8%, a specificity of 87.5%, and an overall accuracy of 87.1%. Significance: The DAME score could serve as a user-friendly score to predict the risk of autoimmune-associated epilepsy in patients with NORSE due to autoimmune encephalitis.