Cumulative Social Disadvantage and Disease Activity in Juvenile Idiopathic Arthritis: A Childhood Arthritis and Rheumatology Research Alliance Registry Study

OBJECTIVE: Social determinants of health (SDOH) contribute to juvenile idiopathic arthritis (JIA) disparities, but most studies have assessed SDOH independently rather than cumulatively across individual, family, and neighborhood levels. Using a socioecological framework, we investigated the relationship among cumulative social disadvantage, neighborhood disadvantage, and JIA disease activity. METHODS: We conducted a retrospective cohort study using the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry (2015-2022). Individual- and family-level SDOH were combined into a cumulative social disadvantage score (range: 0-3), with one point each for public or no insurance, family income less than $50,000 per year, and guardian education of high school level or less. Neighborhood disadvantage was measured using Area Deprivation Index (quartiles). The primary outcome was active disease by clinical Juvenile Arthritis Disease Activity-10 (cJADAS-10). Mixed effects models were generated to assess associations adjusted for demographic and clinical covariates, and causal mediation analysis evaluated whether cumulative social disadvantage mediated the relationship between neighborhood disadvantage and disease activity. RESULTS: Among 9,609 children with JIA with a median follow-up time of 2.1 (interquartile range 0.3-5.8) years, 39.1% had a cumulative social disadvantage score greater than 0 with higher scores correlating with greater neighborhood disadvantage. In adjusted analysis, cumulative social disadvantage was associated with higher odds of active disease (adjusted odds ratio 2.10, 95% confidence interval [CI] 1.73-2.53 for a score of 3 vs 0). A total of 87% (95% CI 38-100) of the effect of neighborhood disadvantage was mediated through cumulative social disadvantage. CONCLUSION: Cumulative social disadvantage is strongly associated with active JIA and mediates much of the effect of neighborhood disadvantage. Interventions addressing multilevel SDOH will be essential to reducing JIA health disparities.