Background: Herpes simplex encephalitis (HSE) is a disease with unfavorable vital and functional prognoses. There are no recent epidemiological data on HSE at a national level using real-life databases, especially in France. This study aimed to report the incidence, the clinical characteristics and outcomes of the patients with HSE.
Methods: We conducted a comprehensive retrospective cohort study on all patients hospitalized for HSE in France between 2015 and 2022 using national hospital discharge databases. Incidence, socio-demographic and clinical characteristics (including comorbidities, seizure, stays' features, intensive care supports) were described. The short- (first stay) and long-term (6-month) outcomes were reported, in terms of mortality and rehospitalizations.
Results: 1425 HSE patients were included (median age 67 [54-77] years old, M/F sex ratio 1.07), giving a mean yearly hospital incidence of 2.3 [2.1-2.5] per 1,000,000 inhabitants. 51.2% of the patients were admitted in ICU (n = 730), of whom 59.0% were mechanically ventilated. The overall mortality during the first stay was 14.3% (n = 204), up to 17.9% for ICU patients. Within 6 months, among the survivors, 10.1% had at least one rehospitalization related to HSE. At 6 months, 16.5% of all patients had died (n = 235), 20.8% for ICU patients.
Conclusion: In France, the incidence of hospitalizations for HSE was 2.3 per 1,000,000 inhabitants with more than half of the patients admitted in ICU and a 6-month in-hospital mortality about 16.5%. This real-life update on the characteristics and severe outcomes of the disease raises awareness among care practitioners, of the serious nature of the disease, and thus can lead to higher vigilance.
Keywords: Encephalitis; Herpes simplex; Incidence; Intensive care; Mortality; Outcomes.
© 2024. Springer-Verlag GmbH Germany, part of Springer Nature.