Association of seizure duration and outcome in refractory status epilepticus

The aim of the study was to identify factors influencing long-term outcome and to evaluate the prognostic power of the Status Epilepticus Severity Score (STESS) in refractory status epilepticus (RSE). We retrospectively extracted data on baseline characteristics, RSE details, and hospital course including complications from all patients treated for RSE in our institution between January 2001 and January 2013. Functional outcome was assessed using the modified Rankin Scale (mRS) and was defined as good when either RSE did not lead to functional decline or when the resulting mRS score was 2 or below. Seventy-one episodes in 65 patients were analyzed. The median follow-up time was 12 weeks (IQR 6–35), two patients were lost to follow-up. Poor functional long-term outcome was observed in 42/69 (60.9 %) episodes. In-hospital mortality occurred in 13/71 (18.3 %) episodes. Multivariable analysis revealed that STESS ≥ 3, longer RSE duration, and sepsis were independently related to poor functional long-term outcome. Receiver operating characteristics (ROC) curve analyses confirmed the cut-off dichotomization into STESS ≥ 3 and STESS < 3 for optimal discrimination between good and poor outcome (AUC = 0.671, p = 0.002, YI = 0.368, NPV = 0.607, PPV = 0.756) and revealed an RSE duration of 10 days as a significant cut-off point associated with outcome (AUC = 0.712, p = 0.012, YI = 0.310; NPV = 0.545, PPV = 0.750). In conclusion, STESS and RSE duration represent relevant scores and parameters impacting long-term outcome after RSE. A shorter RSE duration is associated with better outcome and, therefore, rapid and adequate treatment for seizure termination should be enforced.