Salzburg consensus criteria are associated with long-term outcome after non-convulsive status epilepticus

To investigate differences in long-term survival and short-term neurological deficits in adult patients fulfilling either sub-criterion of the Salzburg Consensus Criteria (SC) for non-convulsive status epilepticus (NCSE).

We retrospectively identified a cohort of patients with first-time NCSE epilepticus at Odense University Hospital from 2014 to 2017. Results of electroencephalograms at admission were dichotomized according to the SC (more than 25 epileptiform discharges/10 s was defined as the fast criterion), and groups were compared statistically through survival analysis and in a logistic regression model adjusting for established prognostic determinants in status epilepticus. Secondary outcomes were the associations between SC and neurological deficits at discharge.

One-hundred and six patients fulfilled the SC and were included in the main analysis. In addition, 27 patients had possible NCSE. The fast criterion was significantly associated with decreased mortality 2 years following NCSE (OR 0.31, 95% CI 0.11-0.85, p = 0.039) in a logistic regression analysis after correction for age, etiology, semiology and comorbidity. None of the individual subcomponents of the slow criterion could explain the difference in survival in an exploratory analysis. Functional outcome did not differ between patients fulfilling fast and slow criteria. Patients with a clinical diagnosis of NCSE not fulfilling the SC more often had non-refractory NCSE and a more favorable functional outcome.

The fast diagnostic criterion for NCSE was identified as a new, independent variable associated with long-term survival after NCSE. The results may allow prognostication in patients with NCSE at the time of diagnosis, which could guide decision-making in the clinical setting.