Objective:

To assess whether neighborhood-level disadvantage is associated with time to initiation of an immunosuppressive therapy (IST) among persons with neuromyelitis optica spectrum disorder (pwNMOSD).

Background:

Little is known about the relationship between neighborhood-level disadvantage and exposure to NMOSD-specific IST. 

Design/Methods:

This is a retrospective cohort study of patients with aquaporin-4 (AQP4)-positive NMOSD diagnosed after the first FDA approved NMOSD-specific IST became available (eculizumab, January 2019). We created four multivariable cox proportional hazards regression models to evaluate whether time from NMOSD diagnosis to first exposure to an NMOSD-specific IST (rituximab, satralizumab, inebilizumab, or eculizumab) was associated with neighborhood disadvantage. Neighborhood disadvantage (yes or no) was defined as being in the most disadvantaged 15% of Americans in terms of financial strength, educational attainment, economic hardship/inequality, or overall area deprivation index (ADI). We adjusted for race, insurance, and education level. 

Results:

We included 38 AQP4-positive NMOSD participants: mean age at diagnosis was 47.6±18.8 years, 82.0% female, 49.0% non-White who were followed for a mean of 1.3±1.1 years since diagnosis. During follow-up for this study, 25 (65.9%) of 38 participants were exposed to an NMOSD-specific IST. Participants who initiated an NMOSD-specific IST did not differ from those who did not in terms of insurance, race, rural-urban commuting area codes, or ADI (p>0.05 for all).  Time from NMOSD diagnosis to initiation of an NMOSD-specific IST did not associate with neighborhood disadvantage, including financial strength (hazard ratio (HR) 0.23, p=0.21), educational attainment (HR 2.76, p=0.18), economic hardship/inequality (HR 0.37, p=0.26), or overall deprivation (HR 0.33, p=0.27).

Conclusions:

Neighborhood disadvantage did not associate with likelihood of exposure or time to initiation of an NMOSD-specific IST, suggesting that disadvantage was not a barrier to treatment in our small cohort. Notably, one-third of pwNMOSD were never exposed to an NMOSD-specific IST, regardless of disadvantage, which warrants further investigation.