The impact of socioeconomic status on subsequent neurological outcomes in multiple sclerosis
Devi Sai Sri Kavya Boorgu, Shruthi Venkatesh, Chirag M. Lakhani, Elizabeth Walker, Ines Aguerre, Claire Riley, Chirag J. Patel, Philip L. De Jager, Zongqi Xia
Abstract
BACKGROUND: To examine whether lower neighborhood-level and individual-level indicators of socioeconomic status (SES) are associated with subsequently worse neurological disability in people with MS (pwMS). METHODS: In a multi-center study using prospectively collected data from discovery cohorts (University of Pittsburgh, N=1316) and replication cohorts (Columbia University, N=488), we calculated a neighborhood SES indicator, area deprivation index (ADI), based on participants' residence at enrollment, and we derived an individual SES indicator based on participants' household income. Patient-reported neurological outcomes included the Multiple Sclerosis Rating Scale-Revised (MSRS-R), Patient-Determined Disease Steps (PDDS), and Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function scores from 2018 to 2020. We performed covariate-adjusted regression analyses in each cohort and then random-effects meta-analyses. RESULTS: Higher ADI (lower SES) in 2015 was associated with subsequently worse neurological outcomes during 2018-2020 (discovery: MSRS-R, β=0.62, 95%CI [0.36,0.89], p<0.001; PDDS, β=0.11, 95%CI [0.02,0.20], p=0.02 | replication: MSRS-R, β=0.46, 95%CI [0.21,0.72], p<0.001; PDDS, β=0.12, 95%CI [0.03,0.21], p=0.009, PROMIS, β=-0.60, 95%CI [-1.12,-0.08], p=0.025). Lower neighborhood percent with college education (MSRS-R, β=-7.31, 95%CI [-8.99,-5.64], p<0.001; PDDS, β=-1.62, 95%CI [-2.20,-1.05], p<0.001; PROMIS, β=9.31, 95%CI [5.73,12.89], p<0.001), neighborhood median household income (MSRS-R, β=-3.80e-05, 95%CI [-5.05e-05,-2.56e-05], p<0.001; PDDS, β=-8.58e-06, 95%CI [-1.28e-05,-4.32e-06], p<0.001; PROMIS, β=2.55e-05, 95%CI [5.96e-07,5.05e-05], p=0.045), and neighborhood median home value (MSRS-R, β=-6.50e-06, 95%CI [-8.16e-06,-4.84e-06], p<0.001; PDDS, β=-1.54e-06, 95%CI [-2.11e-06,-9.65e-07], p<0.001; PROMIS, β=4.98e-06, 95%CI [1.81e-06,8.14e-06], p=0.002) drove the association between higher ADI and subsequently worse neurological disability (in joint analyses). Neighborhood percent of population with Medicaid, but not private insurance, significantly mediated the observed covariate-adjusted associations. Higher individual-level household income bracket was associated with better neurological outcomes in joint analyses (MSRS-R: R=-0.39, p<0.001; PDDS: R=-0.35, p<0.001; PROMIS: R=0.37, p<0.001), independent of ADI. CONCLUSIONS: Lower neighborhood SES is associated with subsequently worse neurological outcomes in pwMS. Future testing of targeted intervention through public policies that improve SES are warranted.