Comparison between Different Disease Activity Scores in Black African Patients with Rheumatoid Arthritis: A Cross-Sectional Multicenter Study

Abstract

Objective: Although the discordance in the disease activity scores based on 28 joints (DAS28) has been widely investigated, few data exist among black African (BA) populations. We aimed first to evaluate the correlation and second to assess the concordance between various DAS28 scores in the BA patients with rheumatoid arthritis (RA). Methods: We conducted a multicenter cross-sectional study in adult patients who had RA from Guinea and Cameroon. These patients were diagnosed according to the 2010 ACR/EULAR criteria. Outcome measures were DAS28-ESR and various DAS28-CRP scores. Paired t-test, agreement kappa coefficient, spearman's correlation coefficient, Bland-Altman plots, and ROC curves were used to analyze different DAS28 scores. Results: Of 74 patients analyzed, 85% were female, mean age of these patients was 50 years, and median disease duration was 36 months (IQR: 12-90). Four DAS28 scores comparisons were performed. DAS28-ESR was on average higher than standard DAS28-CRP (Δ = 0.58, [95% CI: 0.45-0.71]; p < 0.0001) and DAS28-CRP without patient's global VAS assessment (Δ = 0.51 [0.46-0.75]; p < 0.0001). Correlation between DAS28 scores was moderate ranging from 0.6 to 0.82. Overall agreement was lower for the conventional DAS28-ESR (weighted kappa: Range, 37.3% to 55.3%) than Castrejon DAS28-CRP (72.6% to 87.1%). DAS28-CRP-3 has a higher predictive power to evaluate disease activity than DAS28-ESR-3 (AUC, 0.97 [0.95-1.00] vs. 0.80 [0.68-0.91], p = 0.0062). Conclusion: The current study provides information on correlation and discrepancy between different disease activity scores in BA patients with RA, and suggests that these markers were not interchangeable.