Diagnostic value of biochemical markers of bone turnover and postmenopausal osteoporosis

We studied 77 women divided into postmenopausal osteoporotic and premenopausal and postmenopausal non-osteoporotic groups in order to evaluate bone metabolism and diagnostic value of biochemical markers of bone turnover in postmenopausal osteoporosis. Postmenopausal osteoporotic (n: 40), postmenopausal non-osteoporotic (n: 24) and premenopausal non-osteoporotic (n: 13) groups were defined according to bone mineral density (BMD) scores obtained with dual energy X-ray absorptiometry (DEXA). Urinary deoxy-pyridinoline (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 postmenopausal osteoporotic group (8.7 and 18.7 mumol/mg creatinine) were significantly higher than postmenopausal control (5.1 and 11.7 mumol/mg creatinine, p < 0.0001) and premenopausal control (6.0 and 13.0 mumol/mg creatinine, p < 0.0005 and p < 0.001) groups. Bone formation markers were not significantly 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 osteoporosis. This study suggests that bone resorption markers are more efficient than bone formation markers in the diagnosis of postmenopausal osteoporosis. Urinary Dpd/creatinine ratio has the highest diagnostic value.