Epidemiology of status epilepticus in the United States: A systematic review

Convulsive status epilepticus (CSE) is a life-threatening neurologic emergency, which is defined by the International League Against Epilepsy (ILAE) as bilateral tonic-clonic seizure activity lasting longer than 5 min, while absence status epilepticus (SE) and focal SE are specified as exceeding 10 min. Epidemiological evidence on SE is currently lacking, and the incidence is not well-known, especially in light of changes in the ILAE criteria for SE. The objectives of this systematic literature review were to describe the epidemiology of SE in the US population and the associated burden of illness.

A systematic review, including literature and pragmatic searches, was conducted. Literature searches were performed using MEDLINE, Embase, BIOSIS, and Web of Science electronic databases from inception to February 2019. Pragmatic searches of the gray literature were carried out using Google, Google Scholar, conference proceedings, and ClinicalTrials.gov to identify additional sources. Only US-based studies or multinational studies reporting US data of interest were included.

In total, 69 sources were identified. The incidence of all SE in patients of all ages in the USA ranged from 18.3 to 41 per 100,000 people per year. Incidence of all-age CSE rose from 3.5 (1979) to 12.5 (2010) per 100,000 people per year. Status epilepticus incidence followed a bimodal (U-shaped) distribution, with the highest estimates in the first years of life (0-4 years) and after 60 years. Mortality associated with SE varied from 21% over 30 days to 31.2% over 10 years. For CSE, two studies reported similar in-hospital mortalities (9.2% and 10.7%). Median healthcare costs related to SE admission were approximately US$14,500 per adult (17-45 years) and US$8000 per child (0-16 years).

There is a lack of recent data on the epidemiology and healthcare burden associated with SE. Reports of SE incidence in the USA are highly variable and predate the 2015 ILAE definition of SE. However, the available data suggest a high burden of illness.