OBJECTIVES: There are scant data regarding the economic cost of acute treatment for a relapse of NMOSD, a condition characterized by unpredictable relapses that can cause blindness, paralysis and an increased risk of mortality. This study examined relapse-associated healthcare utilization and expenditure among patients with NMOSD in US clinical practice.

METHODS: A retrospective cohort study was conducted using data from a US private healthcare claims database. The study population comprised adults who had evidence of NMOSD (≥1 inpatient diagnosis or ≥2 outpatient diagnoses) between January 2013 and March 2018. Relapses were ascertained from initial observed evidence of NMOSD until the end of follow-up, and were identified based on hospital admissions and ambulatory encounters for disease-related treatment. Healthcare utilization and expenditure (US$2018) during relapses were tallied using amounts paid for treatment-related services.

RESULTS: The study population included 1,118 patients with NMOSD; mean age was 46 (SD: 13) years and 74% were female. During a mean follow-up of 2.1 (SD: 1.6) years, 45% of patients had ≥1 relapse and the annualized rate of relapse among all patients was 0.9 (95% CI: 0.8–1.1). Mean duration of relapse episodes (time between first and last relapse-related encounters), irrespective of care setting, was 16.1 (95% CI: 15.3–16.8) days, and mean expenditure per relapse totaled $10,680 (95% CI: $9,273–12,086). For the 37% of relapses requiring inpatient care, mean duration of hospitalization (time between admission and discharge) was 14.7 (95% CI: 12.0–17.5) days and mean expenditure per relapse totaled $21,121 (95% CI: $17,551–24,692).

CONCLUSIONS: In this large, retrospective, observational study of patients with NMOSD receiving healthcare in US clinical practice, expenditures for acute treatment of a relapse were considerable in both the inpatient and outpatient settings.