Diagnostic value of biochemical markers of bone turnover and postmenopausal osteoporosis

We studied 77 women divided into postmenopausal osteoporotic and premenopau sal and postmenopausal non-osteoporotic groups in order to evaluate bone me tabolism and diagnostic value of biochemical markers of bone turnover in po stmenopausal osteoporosis. Postmenopausal osteoporotic (n: 40), postmenopau sal non-osteoporotic (n: 24) and premenopausal non-osteoporotic (n: 13) gro ups were defined according to bone mineral density (BMD) scores obtained wi th dual energy X-ray absorptiometry (DEXA). Urinary deoxypyridinoline (Dpd) , pyridinoline (Pyd), serum total alkaline phosphatase (ALP), bone specific alkaline phosphatase (BALP), osteocalcin (BGP), total calcium, phosphorus, and creatinine levels were determined. Urinary Dpd and Pyd levels of postm enopausal osteoporotic group (8.7 and 18.7 mu mol/mg creatinine) were signi ficantly higher than postmenopausal control (5.1 and 11.7 mu mol/mg creatin ine. p<0.0001) and premenopausal control (6.0 and 13.0 mu mol/mg creatinine , p<0.0005 and p<0.001) groups. Bone formation markers were not significant ly different between groups, although BGP correlated with Dpd and Pyd (r: 0 .26 and r: 0.31, p<0.05) in osteoporotic subjects. From receiver operating curve (ROC) analysis Dpd had the best diagnostic value (0.846), followed by Pyd (0.802) in evaluation of osteoporosis, whereas BALP (0.570) and BGP (0 .528) were relatively inefficient in the discrimination of postmenopausal o steoporosis. This study suggests that bone resorption markers are more effi cient than bone formation markers in the diagnosis of postmenopausal osteop orosis. Urinary Dpd/creatinine ratio has the highest diagnostic value.