Background/Purpose: To develop a methodology for well-defined rheumatoid arthritis (RA) measurement as an outcome and provide a clear definition of social determinants related to disease activity. We then examine the association between racial and social factors and risk of higher RA disease activity among RA patients.

Methods: The patients studied were from the University of Pittsburgh’s Rheumatoid Arthritis Comparative Effectiveness Research (RACER) registry. Since February 2010, RACER has enrolled patients older than 18 years who have been diagnosed with RA by a rheumatologist. The registry had data to enable generating Disease Activity-C Reactive Protein (DAS28-CRP) for patients’ each visit. We conducted a cross-sectional study using the baseline data. Evaluation for difference between dichotomous variables of outcome (high vs. low DAS28-CRP) was done using Chi-square or Fisher exact tests. Comparisons of continuous variables were performed using t-test or the Wilcoxon test. The multiple logistic regression models were then constructed and adjusted for confounders selected by backwards selection and consideration of clinically relevant covariates.

Results: A total of 729 patients with information available on both baseline DAS28-CRP and a majority of social factors’ were included for the analyses. The mean age was 59.5 (SD=12.7) years, 78% were female, and median RA disease duration was 9.8 (IQR: 3.7, 19.1) years. 45% of patients had high DAS (N=326), about 64% had less than a college degree, 24% had annual income <$25K, and 67% were not-working. High RA disease activity group patients were more likely to be black, smokers, with a higher BMI, lower education level, not working. They were also less likely to be married, with a lower annual income, with abnormal CRP and longer disease duration. For the multiple logistic regression model adjusted for selected confounders, we found that having higher BMI, annual income below $25K, and being not working were statistically significantly associated with increases risk of higher RA activity (Table 2).

Conclusion: The objective of this study is to utilize the well-defined RA cohort to estimate whether there are differences in RA disease activity at baseline for different social and racial factors groups. Our results indicate that significant differences in RA disease activity by social and racial groups may be a reflection of lack of early care and delay in seeking treatment, leading to a more serious and debilitating disease outcome. Outreach into the community at all levels addressing the need for early RA detection and treatment will be needed.