Serum osteocalcin (bone Gla-protein) following corticosteroid therapy in postmenopausal women with rheumatoid arthritis. Comparison of the effect of prednisone and deflazacort.

In 28 postmenopausal women with rheumatoid arthritis, serum osteocalcin (OC) concentration decreased from 5.2 +/- 1.9 ng/ml to 3.0 +/- 1.6 ng/ml after 6 months therapy with corticosteroids (p less than 0.005). No differences, however, were found in a control group of 13 patients treated for 6 months with nonsteroidal anti-inflammatory drugs. In those patients with serial OC measurements, changes in serum OC were already evident within the first month of therapy. This suggests that a suppressed osteoblast function may be detectable early during corticosteroid therapy in rheumatoid arthritis. Fifteen patients treated with prednisone (5-25 mg once daily, mean 12.33 mg/day) showed a more marked decrease in serum OC than 13 patients treated with equivalent doses of deflazacort (p less than 0.005). Prednisone therapy at doses higher than 10 mg/day resulted in a severe suppression of OC values in most cases. The effect of deflazacort was, however, mild in the majority of patients treated with doses of up to 30 mg/day.