Associations between duration of status epilepticus and clinical outcomes in adults: a systematic review

Duration of status epilepticus (SE) is widely considered a key determinant of outcome severity, but its prognostic value is hard to interpret because definitions of seizure onset, termination, and recurrence, as well as analytical handling, differ substantially across studies. We reviewed its association with mortality, functional outcome (motor and/or cognitive impairment), and refractoriness in adults.

We searched MEDLINE (via PubMed), Cochrane CENTRAL, and Scopus for studies examining SE duration in relation to clinical outcomes in adults. We extracted study design, SE phenotype, duration definitions, analytical strategy, and temporal thresholds. Risk of bias was assessed with the QUIPS tool. Outcome-specific associations were synthesized narratively.

Forty-three studies (1994-2025) were included. The definitions and measurement of SE duration, as well as analytical approaches (continuous vs. categorical, with heterogeneous thresholds), varied widely. Mortality was assessed in 31 studies, functional outcome in 26, and refractoriness in 7. Longer duration was more consistently and independently associated with worse functional outcome than with mortality; the weaker mortality signal likely reflects competing determinants such as etiology, premorbid vulnerability, and systemic severity. The evidence on refractoriness was limited but consistent with a link between prolonged seizures and treatment resistance.

SE duration should be interpreted as a context-dependent prognostic marker rather than as an absolute threshold. Its meaning appears to be shaped by the specific outcome, electroclinical phenotype, etiology, and diagnostic approach. Standardized onset and termination criteria, explicit recurrence rules, and harmonized modeling would improve cross-study comparability and strengthen prognostic assessment.