PREDICTORS OF EROSION AND JOINT SPACE NARROWING PROGRESSION IN PATIENTS WITH EARLY RHEUMATOID ARTHRITIS

Background: Joint damage in rheumatoid arthritis (RA) includes erosions and joint space narrowing (JSN). Predictors of these processes, and the underlying mechanisms, require further study1.
Objectives: To investigate the relation between patient characteristics at RA diagnosis and progression of erosions and JSN, over 5 years. Methods: Consecutive early RA patients (symptom duration Results: 233 early RA patients where included. Radiographs at baseline and 5 years were available for 162 patients. Results on predictors of rapid radiographic progression of the total SHS have been reported previ- ously2. The median (interquartile) progression of erosion and JSN scores were 4 (0-8) and 8 (1-16), respectively. RF and anti-CPP predicted pro- gression of erosions and JSN over 5 years, with stronger associations for erosions (Table 1). Baseline erosion- and JSN scores each predicted progression of JSN, while baseline JSN did not predict progression of erosions. In crude analyses, higher disease activity, CRP and ESR were associated with progression of both erosions and JSN, while statistically more robust for the former. Smoking and high levels of Cartilage Oligo- meric Matrix Protein (COMP) (>12 U/L) were both associated with pro- gression of erosions ((B= 0.12, p= 0.016) and (B= 0.12, p= 0.02) respectively) but not JSN, in adjusted analyses (Table 1). Overweight or obesity (BMI >25kg/m2) was associated with less progression of JSN (B= -0.14, p= 0.018, adjusted for RF, age and baseline JSN score).
Conclusion: RF, anti-CCP and markers of inflammation and disease activity predicted progression of erosions and JSN, in particular erosions. Development of erosions may predate cartilage damage leading to JSN. Smoking and high baseline levels of COMP predicted progression of ero- sions, but not JSN. Overweight and obesity may be associated with mechanisms that protect from JSN.