Inpatient care of neuromyelitis optica spectrum disorder in Germany: Nationwide analysis from 2010 to 2021

BACKGROUND: Despite tremendous development in the treatment of neuromyelitis optica spectrum disorder (NMOSD), less is known about the characteristics of hospitalized patients and inpatient care utilization. OBJECTIVE: To investigate the development of inpatient NMOSD case numbers and implemented immunotherapies in the last decade in Germany. METHODS: We conducted a nationwide retrospective study using an administrative database of all hospitalized NMOSD patients between 2010 and 2021. We evaluated yearly data on case numbers, demographics, treatment regimens, and seasonal variations of apheresis therapy as a surrogate marker of severe relapse incidence. RESULTS: During the observational period case number of inpatients substantially increased (2010:n = 463, 2021:n = 992). The mean age was 48.1 ± 2.5 years (74% females). The pooled yearly rate of plasmapheresis/immunoadsorption was 14% (95% CI [13–15%]), without seasonal variations. Its application peaked in 2013 (18%, 95% CI [15–21%]) with decreasing trend since. Predominant immunotherapy was rituximab (40%, 95% CI [34–45%]), followed by tocilizumab (4%, 95% CI [3–5%]) since 2013 and eculizumab (4%, 95% CI [3–5%]) since 2020. Inpatient mortality ranged between 0% and 1% per year. CONCLUSIONS: Inpatient case numbers of NMOSD substantially increased during the past decade, probably reflecting improving disease awareness. In parallel with the administration of highly effective therapies rate of apheresis therapies decreased. A stable apheresis rate over the year makes seasonal variations of the steroid-refractive relapses unlikely.