LAUSR

OBJECTIVES To understand the relationships between deprivation and obesity with self-reported disability and disease activity in people with RA; and whether BMI mediates the relationship between area-level deprivation and these outcomes. METHODS Data came from the Rheumatoid Arthritis Medication Study (RAMS), a one-year multicentre prospective observational cohort of people with RA recruited from rheumatology centres across England commencing methotrexate for the first time. 1529 and 1626 people were included who had a baseline and at least one follow-up measurement at 6 or 12 months of Health Assessment Questionnaire-Disability Index (HAQ-DI) and Disease Activity Score-28 (DAS28), respectively. Linear mixed models estimated the associations of deprivation and obesity with repeated measures HAQ-DI and DAS28. Causal mediation analyses estimated the mediating effect of BMI on the relationship between deprivation and RA outcomes. RESULTS Higher deprivation and obesity were associated with higher disability (adjusted regression coefficients highest vs lowest deprivation fifths 0.32 (95% CI 0.19, 0.45); obesity vs no obesity 0.13 (95% CI 0.06, 0.20)) and higher disease activity (adjusted regression coefficients highest vs lowest deprivation fifths 0.34 (95% CI 0.11, 0.58); obesity vs no obesity 0.17 (95% CI 0.04, 0.31)). BMI mediated part of the association between higher deprivation and self-reported disability (14.24%) and disease activity scores (17.26%). CONCLUSIONS People with RA living in deprived areas have a higher burden of disease, which is partly mediated through obesity. Weight-loss strategies in RA could be better targeted towards those living in deprived areas.