Background Socioeconomic status (SES) may affect outcomes in a chronic disease due to health related behaviors and/or access to healthcare including physician visits and medications. Early rheumatoid arthritis outcomes may be affected in a country with universal healthcare (for physician visits) but not medications.
Objectives To assess the impact of socioeconomic status (SES) on outcomes in patients with early inflammatory arthritis using data from the Canadian Early Arthritis Cohort (CATCH) study.
Methods The CATCH cohort recruited 2023 patients prospectively with early RA (confirmed or suspected), and allocated to low- or high-SES groups based on education and income. Outcomes at baseline and 12 months were analyzed in relation to SES including the Disease Activity Score (DAS28), Simplified Disease Activity Index (SDAI), pain, patient global assessment scale (PTGA), the Health Assessment Questionnaire Disability Index (HAQ), and the SF12-v2 Health Survey, using the analysis of variance (ANOVA), Chi-squared test and regression analyses.
Results The CATCH patients had 43% with high school education or less and 37% in the low-income group (<$50,000 Canadian per annum household income). The low-education group had higher DAS28 (p=0.045) at baseline becoming non-significant at 12 months. Patients in the low-income group presented with higher HAQ (p=0.017), pain (p=0.035), PTGA (p=0.004), and SDAI (p=0.022). Low-income vs. high-income groups were associated with an odds ratio (OR) above the median for: HAQ 1.20 (95% CI 1.00-1.45), PTGA 1.27 (95% CI 1.06-1.53), and SDAI 1.25 (95% CI 1.02-1.52) at baseline. The predictive value of low income for HAQ persisted at 12 months, OR 1.30 (95% CI 1.02-1.67) but not for other variables. Characteristics of the CATCH patients (0.001# is P<0.001).
Conclusions Low SES is associated with higher disease activity, poorer physical function, more pain, higher PTGA, and higher HAQ at baseline. HAQ remains worse at one-year follow-up in this population.
Disclosure of Interest : G. Yang: None declared, V. Bykerk: None declared, B. Haraoui: None declared, C. Thorne: None declared, D. Tin: None declared, C. Hitchon: None declared, G. Boire: None declared, E. Keystone: None declared, J. Pope Grant/research support: The CATCH study was designed and implemented by the investigators and financially supported initially by Amgen Canada Inc. and Pfizer Canada Inc. via an unrestricted research grant since inception of CATCH. As of 2011, further support was provided by Hoffmann-La Roche Ltd., United Chemicals of Belgium (UCB) Canada Inc., Bristol-Myers Squibb Canada Co., AbbVie Laboratories Ltd., and Janssen Biotech Inc.