The impact of revised definitions on the epidemiology of status epilepticus: A population-based study.

Objective: Status epilepticus (SE) represents one of the most common neurological emergencies. The International League Against Epilepsy (ILAE) redefined SE duration thresholds from 30 to 5 min for convulsive SE in 2015. We conducted a prospective population-based study to determine SE incidence and outcomes under the revised criteria and compared findings with historical data using the 30-min definition.

Methods: A prospective, population-based cohort study was conducted over a period of 18 months to determine the incidence of SE in Germany, replicating the methodology of a first study conducted in this region in 1999. The study included all adults residing within the 35-postcode area, with participation from all regional hospitals and emergency departments. SE cases were prospectively identified and reported. To ensure comparability with the historical data, the analysis focused on the Primary Service Area (PS-Area)-the direct catchment region of the University Hospital Marburg.

Results: A total of 180 adults with SE (96 men, mean age 66.47 years, SD ± 18.5 years, range: 20-94 years). The crude annual incidence in the PS-Area increased from 15.8/100 000 (95% confidence interval [CI] 11.2-21.6) in 1999 to 29.4/100 000 adults (95% CI 20.5-40.0). It was higher in men than in women (30.9 vs 28.1/100 000, p = .11) and in patients ≥60 years (68.5 vs 13.5/100 000; p < .0001). The calculated age- and gender-adjusted incidence was 32.5/100 000 in the PS-Area. The case-fatality rate was 5.77% (95% CI 1.2%-12.7%) and the crude annual cause-specific mortality rate per 100 000 is 1.70 (95% CI 0.21-4.73). In 53% SE was the first seizure episode; only 47% had a history of epilepsy. When extrapolating these findings to the entire German population, there were at least 20 000 cases of SE with 1000 associated deaths annually.

Significance: These findings provide new epidemiologic evidence that the incidence of SE has increased by ~12% with the adoption of the ILAE 2015 definition, underscoring the impact of updated diagnostic criteria on epidemiological estimates.