Background and Objectives: To evaluate the standardized mortality ratio (SMR) of patients in the United States referred to a multidisciplinary clinic for treatment of functional seizures. Methods: We identified patients who had or had not died based on automated retrospective review of electronic health records from a registry of patients referred to a single-center multidisciplinary functional seizures treatment clinic. We calculated an SMR by comparing the number of observed deaths with the expected number of deaths in an age-matched, sex-matched, and race-matched population within the same state, and year records were available. Results: A total of 700 patients with functional seizures (mean age 37 years, 78% female) were followed up for 1,329 patient-years for a median of 15 months per patient (interquartile range 6-37 months). We observed 11 deaths, corresponding to a mortality rate of 8.2 per 1,000 patient-years and an SMR of 2.4 (95% confidence interval: 1.17-4.22). Five of 9 patients with identified circumstances around their death were in hospice care when they passed. None of the identified causes of death were related to seizures directly. Discussion: These data provide further evidence of elevated mortality in functional seizures soon after diagnosis and referral to treatment. These data from the decentralized health care system of the United States build on the findings from other countries with large-scale health registries.
