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

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.