Is bone turnover a determinant of bone mass in rheumatoid arthritis?

Objective. To study the relationship between bone turnover markers and bone mineral density in patients with rheumatoid arthritis. Methods. We studied 54 patients, 24 of whom were receiving low dose steroid s, and compared them to 54 age and sex matched controls. Results. An 8.2% decrease of femoral neck bone mineral density (BMD) was fo und in patients not taking steroids compared with controls (confidence inte rval 1.2-15.3%). Serum markers of bone turnover - namely, procollagen type I C-terminal propeptide (PICP) and procollagen type I N-terminal propeptide (PINP), which reflect bone formation, and procollagen type I C-terminal te lopeptide, which reflects bone resorption - were significantly increased co mpared with controls (p < 0.05, p < 0.01, p < 0.01, respectively). Both PIN P levels and PICP levels were correlated with the femoral neck BMD as well as osteocalcin levels: R = -0.32 (p < 0.05), R = -0.29 (p < 0.05), and R = -0.42 (p < 0.01), respectively. The best independent predictors of bone mas s (stepwise multiple regression analysis) at the femoral neck were steroid use, osteocalcin levels, age, height, the presence of rheumatoid factor, an d the Health Assessment Questionnaire score, which explained 61.6% of the v ariance in femoral neck BMD. Conclusion. Elderly patients with RA using steroids with severe disease and high levels of osteocalcin have marked osteoporosis at the hip.