Osteocalcin in patients with rheumatoid arthritis--effect of anatomical stages, inflammatory activity and therapy

The aim of this study was to investigate whether the degree of inflammatory activity, the anatomical stage and various treatments have an influence on bone turnover in patients with rheumatoid arthritis (RA). Osteocalcin (OC) and other parameters of bone turnover were measured in 131 patients with RA. The mean values of alkaline phosphatase (AP), but not of OC were significantly (P < 0.01) higher in our patients compared to controls. In contrast to AP, OC values increased and correlated significantly (r = +0.33, P < 0.01) with ascending anatomical stage in women not on glucocorticoid treatment. As regards therapy, we found significantly lower OC levels in women receiving steroids compared to controls (P < 0.03) and those being treated with non-steroidal anti-inflammatory drugs (NSAIDs) (P < 0.03), methotrexate (MTX) (P < 0.05), or gold (P < 0.01). Females treated with gold had higher OC levels than patients receiving no antirheumatic drugs (P < 0.03). Furthermore, there was a significantly negative correlation between OC and inflammatory activity [C-reactive protein (CRP)] (r = -0.25, P < 0.003). In conclusion, OC levels were significantly higher (P < 0.032) in patients with advanced (anatomical) stages of RA. In contrast to AP, changes in bone turnover, such as suppression of bone formation by steroids and high inflammatory activity in patients with RA, were easily detected.