Black and Non-Hispanic White persons with multiple sclerosis: Social determinants of health and health inequities

Abstract Objective: Distinctive differences in multiple sclerosis (MS) disease severity, progression, and mortality have been observed among different races. Social determinants of health (SDH) can contribute to such racial disparities. This study aims to: 1) compare Non-Hispanic White (NHW) and Black (Bl) persons with MS in terms of MS and SDH; 2) explore the impact of SDH-adjustment in the association between race and Expanded Disability Status Scale (EDSS), Timed 25-Foot Walk (T25-FW), 9-Hole Peg Test (9-HPT), Symbol Digit Modalities Test (SDMT). Methods: 120 patients, self-identified as Bl (n = 60) or NHW (n = 60) persons, were included in this cross-sectional analysis from a prospectively enrolled cohort. We used parametric and non-parametric tests; logistic models were performed to select the most relevant SDH. Univariable linear regression models were used to explore differences in EDSS, T25-FW, 9-HPT, SDMT and models were adjusted for relevant SDH using propensity scores (PS). Results: Significant racial disparities in adverse SDH were identified in Black persons with MS (BpwMS). BpwMS patients had a higher EDSS (β=0.66, p = 0.022), log-transformed T25-FW (β=0.16, p = 0.001), 9-HPT (β=2.89, p = 0.001) and lower SDMT (β=-5.97, p = 0.003); after PS-adjustment, associations were no longer significant except for T25-FW (β=0.13, p = 0.030) and the magnitude of all coefficients was reduced (EDSS: -27 %, T25-FW: -19 %, 9-HPT: -36 %, SDMT: -45 %). Interpretation: More efforts are necessary to adequately address the SDH that distinguish Bl from NHW persons with MS; additional unknown or unmeasured variables, including biologic differences as well as other SDH, should be explored to elucidate the mechanisms behind worse MS outcomes in BpwMS.