Circulating dickkopf-1 and radiological progression in patients with early rheumatoid arthritis treated with etanercept.

### Objective Dickkopf-1 (Dkk-1) regulates bone remodeling in animal models of inflammatory arthritis, but its role in patients with rheumatoid arthritis (RA) remains unclear. ### Methods Baseline circulating Dkk-1 was measured in 113 patients with RA (< 3 yrs) who received etanercept (10 or 25 mg twice/week, n = 63) or methotrexate alone (n = 40) for 1 year. Progression was assessed by changes in radiological Sharp score. ### Results Increased Dkk-1 was associated with a higher risk of progression of bone erosion, independently of age, sex, baseline radiological damage, C-reactive protein, and disease activity in patients treated with etanercept. ### Conclusion Dkk-1 may be an important mediator of bone erosion in patients with RA.