Background

Neuromyelitis optica spectrum disorder (NMOSD) is a rare autoimmune disease of the central nervous system that may be associated with specific comorbidities, including autoimmune disease (AID) or nonautoimmune conditions. This study assessed real-world healthcare utilization and cost of illness in patients with NMOSD and overlapping AID.

Objectives

To evaluate the cost of illness in patients with NMOSD with overlapping AID compared with controls without NMOSD (non-NMOSD) and NMOSD without comorbid AID in US commercial claims databases.

Methods

Methods

Claims data from the Truven Health MarketScan Commercial and Medicare Supplemental Databases were analyzed 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. Continuous enrollment ≥6 months before and ≥1 year after the first claim (index date) was required. Non-NMOSD controls were matched 5:1 to patients with NMOSD. Total costs stratified by AID in consumer price index–adjusted 2019 US dollars within 12 months post–index date were calculated for each patient.

Results

In the NMOSD group, 31/162 patients (19.1%) had AID compared with 40/810 matched non-NMOSD controls (4.9%), with 8/162 (4.9%) in the NMSOD group having multiple AIDs vs 5/810 (0.6%) in matched non-NMOSD controls. These included systemic lupus erythematous (SLE; 5.6% vs 0.4%; p<0.001), rheumatoid arthritis (RA; 4.3% vs 0.9%; p=0.004), Sjögren syndrome (SS; 3.1% vs 0.1%; p<0.001), and autoimmune encephalitis (AE; 2.5% vs 0%; p<0.001). Total median [IQR] costs per patient during the post-index follow-up period were significantly higher for patients with NMOSD and AID ($68,386 [$23,374–$160,863]) than both matched non-NMOSD controls with AID ($17,215 [$6,715–$31,442]; p<0.001) and NMOSD without AID ($23,905 [$8,633–$67,252]; p=0.022). This trend held across all settings, including inpatient care, outpatient care, outpatient emergency room services and pharmacy expenses.

Conclusions

Patients with NMOSD and comorbid AID incurred significantly higher costs associated with healthcare resource utilization compared with matched non-NMOSD controls and patients with NMOSD who did not have AID. These results demonstrate a higher cost burden associated with overlapping AID (primarily SLE, RA, SS and AE) in patients with NMOSD and a need to identify more cost-efficient, integrated therapeutic approaches to address the overlap of NMOSD and other serious, debilitating AID.