Neuromyelitis optica spectrum disorder (NMOSD) is a rare autoimmune condition of the central nervous system that may be associated with concomitant autoimmune disease (CAID), such as systemic lupus erythematosus (SLE) or rheumatoid arthritis (RA), as well as nonautoimmune conditions (CnAID).
To evaluate the burden of CAID in patients with NMOSD compared with controls without NMOSD (non-NMOSD) in US commercial claims databases.
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. The Charlson Comorbidity Index (CCI) was assessed during a 6-month baseline period prior to NMOSD diagnosis and at 12 months post-index. Comorbidities during the 12-month follow-up period were evaluated.
A total of 162 patients with NMOSD (mean [SD] age, 43.3 [18] years) and 810 non-NMOSD controls (mean [SD] age, 43.3 [18] years) were evaluated. Mean (SD) 6-month baseline and 12-month follow-up CCI scores were 0.96 (1.77) and 1.62 (2.53) for patients with NMOSD vs 0.34 (0.91) and 0.52 (1.31) for non-NMOSD controls, respectively (p<0.001). CAID occurred in 19.1% vs 4.9% (p<0.001) of NMOSD patients vs non-NMOSD controls. SLE (5.6% vs 0.4%; p<0.001), RA (4.3% vs 0.9%; p=0.004), Sjögren syndrome (3.1% vs 0.1%; p<0.001) and autoimmune encephalitis (2.5% vs 0%; p<0.001) occurred at significantly higher prevalence in patients with NMOSD. Reports of type 1 diabetes (1.9% vs 1.4%) and myasthenia gravis (1.2% vs 0.1%) were not significantly different between the NMOSD and non-NMOSD groups in this study cohort.
Patients with NMOSD had significantly higher CCI scores and CAID prevalence compared with controls. Consistent with previous studies, these results highlight the significant CAID burden in NMOSD. Moreover, these data suggest immune dysfunction common to multiple autoimmune diseases and underscore the need to identify efficacious therapies with distinct mechanisms of action to address the concomitant burden of NMOSD and other debilitating CAIDs.