Serum osteocalcin levels in patients with psoriatic arthritis: an extendedreport

The aim of the study was to investigate the rate of bone formation in patie nts with psoriatic arthritis (PsA compared to controls and patients with ps oriasis vulgaris without PsA (PS). Ostcocalin (OC) and other parameters of bone turnover were measured in 32 patients with PsA and 17 patients with PS and compared to controls (n = 50). Patients with PsA do not generally pres ent with different OC levels(3.0 +/- 1.6 ng/ml), than controls (3.6 +/- 1.1 7 ng/ml), if disease activity or sex are not considered. Women with PsA had significantly lower OC levels (2.8 +/- 0.34 ng/ml) than female controls (4 .11 +/- 1.7 ng/ml) or women with PS (3.0 +/- 0.89 ng/ml). However, mean dis ease activity(2.27 +/- 1.0 vs 2.95 +/- 0.92) was also significantly lower i n women than men. Furthermore, we found a significant correlation between a lkaline phosphatase (AP) and OC in all patients with PsA (r = 0.49, P < 0.0 5), Disease activity of PsA had an influence on OC levels, Patients with no disease activity had lower OC levels (2.2 +/- 0.7 ng/ml) than patients wit h a high activity (OC 3.92 +/- 1.25, P < 0.05). Similar results were obtain ed with alkaline phosphatase. In addition, we found a significant correlati on between clinical activity and OC (r = 0.38, P < 0.02) and alkaline phosp hatase (r = 0.49. P < 0.01). Patients with PsA show a corresponding increas e in OC levels, if disease activity is high. The proliferative changes in a ctive PsA may be related to inflammatory mechanisms coupled with bone forma tion.