Hospital resource use and costs in autoimmune encephalitis: a single-center retrospective cohort study

BACKGROUND: Autoimmune encephalitis (AE) causes substantial but insufficiently quantified hospital resource use. We aimed to estimate direct hospital costs of acute AE care and identify factors associated with prolonged length of stay (LOS). METHODS: We conducted a single-center retrospective cohort study of patients with an index admission fulfilling criteria for probable or definite AE (2011–2021). Direct hospital costs within 1 year after index admission were estimated from the UKER hospital/provider perspective by applying standardized German unit costs (price year 2020) to observed non-ICU ward days, ICU days, and neurology outpatient visits. Associations with total costs were assessed using univariable OLS regression; contributors to prolonged LOS were extracted from chart review. RESULTS: Thirty-five patients (16 female, 46%; median age 63 years [IQR 42–73]) were included (2011–2021). CNS-targeting antibodies were detected in 74%. Median LOS was 26 days (IQR 13–38), and 11 patients (31%) required ICU care. Median direct hospital costs per patient within the first year were EUR 26,547 (USD 30,264). ICU-admitted patients incurred higher hospital costs than non-ICU patients (EUR 69,822 vs. EUR 20,234 per patient; p < 0.001). LOS, particularly ICU LOS, was a major cost driver. Delayed diagnosis, prolonged immunotherapy, insufficient treatment response, medical complications, and ICU admission contributed to longer LOS and higher costs. Costs did not differ between seropositive and seronegative patients, but varied by antibody subtype, with NMDA-R positivity associated with higher costs. CONCLUSION: AE is associated with substantial direct hospital costs, especially among ICU-admitted patients. Optimizing diagnostic workflows and timely initiation of immunotherapy may reduce LOS and resource use and improve outcomes.