OBJECTIVES: Neuromyelitis optica spectrum disorder (NMOSD) is a rare autoimmune disease of the central nervous system that leads to accumulation of severe neurological disability. Limited data have been published on the cost of illness with NMOSD, including in the emergency room (ER) and inpatient hospital settings. This study evaluated the cost of illness related to ER visits and hospitalizations in patients with NMOSD compared with non-NMOSD controls in a US commercial claims database.

METHODS: This study used claims from the Truven Health MarketScan Commercial and Medicare Supplemental Databases between 2014 and 2018. Patients were identified as having NMOSD if they had ≥1 inpatient or ≥2 outpatient claims for NMOSD diagnosis ≥60 days apart or ≥2 claims for transverse myelitis diagnosis in combination with ≥1 claim for optic neuritis ≥6 months apart. The first claim was the index date; continuous enrollment ≥6 months before and ≥1 year after the index date was required. Non-NMOSD controls were matched 5:1 to patients with NMOSD. Total costs of ER visits and hospitalizations in consumer price index–adjusted 2019 US dollars within 12 months post–index date were calculated for each patient.

RESULTS: A total of 162 patients with NMOSD and 810 non-NMOSD controls were evaluated. ER visits and hospitalizations for NMOSD vs non-NMOSD groups occurred in 35.8% vs 16.9% and 41.4% vs 5.1 % of patients (p<0.0001 for both), and mean (SD) time in the hospital was 21.2 (32.7) vs 5.24 (6.46; p=0.0006) days, respectively. Mean (SD) costs per patient were $2,400 ($7,771) vs $408 ($2,579) for ER visits and $29,054 ($144,872) vs $1,521 ($10,759) for hospitalizations (p<0.0001 for both) for the NMOSD vs non-NMOSD groups, respectively.

CONCLUSIONS: Compared with non-NMOSD controls, patients with NMOSD incurred significantly higher costs associated with ER visits and hospitalizations, highlighting the need for more efficacious treatments for NMOSD.