Biochemical markers of bone turnover in rheumatoid arthritis. Relation to anti-inflammatory treatment, sex, and menopause

Abstract

Bone turnover was determined in 125 patients with rheumatoid arthritis (RA). Bone Gla protein (BGP) and alkaline phosphatase (AP) were used as markers of bone formation. Fasting urinary calcium relative to creatinine (FU Ca/Cr) and fasting urinary hydroxyproline relative to creatinine (FU Hpr/Cr) were used as markers of bone resorption. These variables were compared to the values of two groups of normal controls in order to elucidate the pathophysiology of the osteopenia occurring in patients with RA. When the patients were divided into groups according to treatment (gold salts, penicillamine, or glucocorticoids), serum AP was highly significantly increased in all three groups, whereas serum BGP was below the normal mean. FU Ca/Cr and FU Hpr/Cr were moderately decreased in the groups treated with gold salts or penicillamine, but increased in the glucocorticoid-treated group. When divided according to sex and menopausal state and glucocorticoid treatment versus non-glucocorticoid treatment, there was a balance between bone formation and bone resorption parameters in all groups, except glucocorticoid-treated men and premenopausal women who had increased values of bone resorption parameters.