Independent external validation of the status epilepticus severity score

OBJECTIVES:: A clinical scoring system for patients with status epilepticus was developed for predicting outcome, planning the level of monitoring needed, and guiding treatment. The aim was to confirm the external validity and transportability of the Status Epilepticus Severity Score prediction functions for outcome in adult patients with status epilepticus. DESIGN:: Observational cohort study. SETTING:: Tertiary academic medical care center. PATIENTS:: Consecutive adult ICU patients with status epilepticus. INTERVENTIONS:: None. MEASUREMENTS AND MAIN RESULTS:: History of seizures, age, seizure type, and level of consciousness were determined at status epilepticus onset, in order to calculate the Status Epilepticus Severity Score. The main outcome measure was the ability to accurately predict the outcome of status epilepticus by measures of discrimination and calibration. Among 171 status epilepticus patients with a mean age of 64.1 years (± 16.3), mortality was 18%. The receiver operating characteristic curve for prediction of death by the Status Epilepticus Severity Score had an area under the curve of 0.744 with an optimal cutoff point greater than or equal to 4. Hosmer-Lemeshow statistics revealed good calibration of the Status Epilepticus Severity Score (chi-square goodness-of-fit test = 1.39; p = 0.845). CONCLUSIONS:: This study is the first independent external validation of the predictive accuracy of the Status Epilepticus Severity Score and its transportability to ICU patients with status epilepticus. Measures of discrimination and calibration indicated that Status Epilepticus Severity Score performed reasonably well on our cohort of ICU patients with status epilepticus. However, the specific optimal cutoff point for survival versus death in our cohort was different than proposed.