Racial and ethnic disparities in disease activity and function among persons with rheumatoid arthritis from university-affiliated clinics.

OBJECTIVE: Health outcomes in rheumatoid arthritis (RA) have improved significantly over the past 2 decades. However, research suggests that disparities exist by race/ethnicity and socioeconomic status, with certain vulnerable populations remaining understudied. Our objective was to assess disparities in disease activity and function by race/ethnicity and explore the impact of language and immigrant status at clinics serving diverse populations.
METHODS: We examined a cross-sectional study of 498 adults with confirmed RA at 2 rheumatology clinics: a university hospital clinic and a public county hospital clinic. Outcomes included the Disease Activity Score in 28 joints (DAS28) and its components, and the Health Assessment Questionnaire (HAQ), a measure of function. We estimated multivariable linear regression models including interaction terms for race/ethnicity and clinic site.
RESULTS: After adjusting for age, sex, education, disease duration, rheumatoid factor status, and medication use, clinically meaningful and statistically significant differences in DAS28 and HAQ scores were seen by race/ethnicity, language, and immigrant status. Lower disease activity and better function was observed among whites compared to nonwhites at the university hospital. This same pattern was observed for disease activity by language (English compared to non-English) and immigrant status (US-born compared to immigrant) at the university clinic. No significant differences in outcomes were found at the county clinic.
CONCLUSION: The relationship between social determinants and RA disease activity varied significantly across clinic setting with pronounced variation at the university, but not at the county clinic. These disparities may be a result of events that preceded access to subspecialty care, poor adherence, or health care delivery system differences.