Early Rheumatoid Arthritis Presentation, Treatment, and Outcomes in Aboriginal Patients in Canada: A Canadian Early Arthritis Cohort Study Analysis

Abstract

Objective. Health inequities exist in chronic diseases for Aboriginal people. This study compared early rheumatoid arthritis (RA) presentation, treatment, and outcomes between Aboriginal and white patients in a large Canadian cohort study. Methods. Longitudinal data from the Canadian Early Arthritis Cohort, a prospective multicenter early RA study, were analyzed for participants who self-identified as Aboriginal or white ethnicity. Disease characteristics at presentation, prognostic factors, frequency of remission, and disease-modifying therapy strategies were contrasted between population groups. Linear mixed models were used to estimate rates of change for disease activity measures over a 5-year period. Results. At baseline, 2,173 participants (100 Aboriginal and 2,073 white) had similar mean +/- SD symptom duration (179 +/- 91 days), 28-joint Disease Activity Scores (DAS28; 4.87 +/- 1.48), and Health Assessment Questionnaire (0.88 +/- 0.68) scores. Factors associated with poor prognosis were more frequently present in Aboriginal participants, but disease-modifying therapy selection and frequency of therapy escalation was similar between the 2 groups. DAS28 remission was achieved less frequently in Aboriginal than in white participants (adjusted odds ratio 0.39 [95% confidence interval 0.25-0.62]). Results were primarily driven by slower improvement in swollen joint counts and nonsignificant improvement in patient global scores in Aboriginal participants. Pain levels remained higher in Aboriginal patients. Conclusion. Aboriginal early RA patients experienced worse disease outcomes than their white counterparts. This may reflect unmeasured biologic differences and/or disparities in prognostic factors informed by inequities in determinants of health. The appropriateness of current treatment strategies applied in different contexts should be considered.