Serological bone markers and joint damage in early polyarthritis.

OBJECTIVE

To investigate the relationship between osteocalcin (OC), a marker of bone formation, and the recently developed serum marker of bone resorption, beta-C-telopeptide (beta-CTx), and radiographic damage in patients with early oligo- and polyarthritis.

METHODS

Patients with peripheral arthritis of > or = 2 joints and < 2 years of symptom duration were studied. The OC and beta-CTx concentrations at baseline were correlated with disease activity and radiographic damage at baseline, and with radiographic progressive disease after 2 years (delta Sharp/van der Heijde score > or = 5). The additional value of serum bone metabolism markers to predict radiographic progressive disease was compared to that of established prognostic factors by multivariate logistic regression analysis.

RESULTS

Two hundred seventy-nine patients (67% female; median age 56 yrs, range 18-83) were included in the study, of whom 73% were diagnosed with rheumatoid arthritis (RA). Baseline levels of beta-CTx (p < 0.05) were significantly correlated with baseline radiographic damage whereas OC was not. beta-CTx was also significantly (p < 0.001) related to measures of disease activity like erythrocyte sedimentation rate, C-reactive protein, and the disease activity score DAS28. Radiographic progressive disease after 2 years corresponded univariately with increased levels of beta-CTx (p < 0.001), but not with OC. In multivariate analysis, beta-CTx was not superior to other measures of radiographic progressive disease such as autoantibodies and disease activity.

CONCLUSION

Increased serum levels of the bone turnover marker beta-CTx are associated with radiographic damage at baseline and radiographic progression after 2 years. However, beta-CTX is less predictive than markers already in use.