Mortality in functional seizures: Evidence from a large electronic health records dataset

OBJECTIVE: Several studies have found that people with functional seizures (FS) have increased mortality, approaching that of epilepsy (epileptic seizures [ES]). The small numbers of deaths in these studies make it unclear whether they can be attributed to comorbidities. We used a very large electronic health database to compare mortality in FS and ES, controlling for comorbidity. METHODS: We searched the TriNetX database for people with FS and no ES, people with ES and no FS, and people with neither FS nor ES (NS). We compared mortality while controlling for demographics and comorbid conditions. RESULTS: We identified 1 916 787 people with ES, 32 854 people with FS, and 21 053 667 healthy controls. FS had rates of mental and physical comorbidities that were higher than NS and, for most categories, higher than ES. The risk of death (hazard ratio [HR]) in ES compared to FS was 2.99 (95% confidence interval [CI] = 2.81-3.18), which was reduced to 2.07 (95% CI = 1.92-2.24) when matched for 31 demographic and health factors. The risk of death in NS compared to FS was .56 (95% CI = .53-.59); after matching for demographics and mood disorders, this was .48 (95% CI = .44-.53). Matched sensitivity analyses suggest this was particularly pronounced in the year following diagnosis (HR = .39, 95% CI = .33-.47) and in the 5th decade of life (HR = .38, 95% CI = .27-.52). SIGNIFICANCE: FS confers approximately doubled mortality over that conferred by its comorbidities, although still only half of that conferred by ES, most prominently after diagnosis and in early middle age.