Relationship of multi-biomarker disease activity score and other risk factors with radiographic progression in an observational study of patients with rheumatoid arthritis

OBJECTIVES To evaluate the multi-biomarker disease activity (MBDA) score as a predictor of radiographic progression and compare it with other risk factors among patients with established RA receiving non-biologic DMARDs. METHODS For 163 patients with RA, we assessed 271 visits for MBDA score (scale of 1-100), clinical data and subsequent 1-year radiographic progression (change in Sharp-van der Heijde score [SHS]). Scatter plot and non-parametric quantile regression curves evaluated the relationship between the MBDA score and change in SHS. Changes in joint space narrowing and erosions were compared among MBDA categories with Wilcoxon rank-sum tests. The ability of the MBDA score to independently predict progression was determined by multivariate models and cross-classification of MBDA score with other risk factors. Generalized estimating equation methodology was used in model estimations to adjust for same-patient visits, always ≥1 year apart. RESULTS Patient characteristics included 67% female, 66%/67% RF(+)/anti-CCP(+); mean age 55 years, MBDA score 43 (moderate = 30-44); median disease duration 4.6 years, SHS 23. Radiographic progression was infrequent for low MBDA scores. Relative risk for progression increased continuously as the MBDA score increased, reaching 17.4 for change in SHS >5 with MBDA scores ≥60. Joint space narrowing and erosion progression were associated with MBDA score. MBDA score was associated with radiographic progression after adjustments for other risk factors. MBDA score significantly differentiated risk for progression when swollen joint count, CRP or DAS28-CRP was low, and among seropositive patients. CONCLUSION MBDA score enhanced the ability of conventional risk factors to predict radiographic progression in patients with established RA receiving non-biologic DMARDs.