Bone turnover markers for osteoporotic status assessment? A systematic review of their diagnosis value at baseline in osteoporosis.

OBJECTIVE: Osteoporosis diagnosis is based on bone mineral density (BMD) but bone remodeling is also a crucial issue. It can be assessed by bone turnover markers (BTMs). Their interest for the positive and etiological diagnosis of osteoporosis at baseline, and their predictive value for past asymptomatic vertebral fractures, were evaluated by a systematic review of the literature. METHODS: Medline database was searched to identify all published reports analyzing BTMs and BMD or fractures. We conducted meta-analyses on BTMs levels according to osteoporotic status using random effects models. RESULTS: Moderate and negative correlations were found, mainly in postmenopausal women, between BTMs and BMD, especially with bone alkaline phosphatase (bone ALP), osteocalcin, serum C-terminal and urine N-terminal crosslinking telopeptides of type I collagen (sCTX and uNTX). Bone ALP and sCTX levels are higher in osteoporotic patients compared to controls. High levels of bone ALP in primary hyperparathyroidism and low levels of osteocalcin in endogenous hypercorticism are the most relevant data reported in endocrine diseases associated with osteoporosis. High levels of BTMs, especially osteocalcin, bone ALP or sCTX, may be associated with prevalent vertebral fractures. CONCLUSION: The diagnosis value of BTMs at baseline in osteoporosis is very low. The interest of BTMs for the etiological diagnostic of secondary osteoporosis has not been demonstrated. Data are lacking to address the interest of BTMs assessment to screen for vertebral fractures in asymptomatic patients with high risk factors of fractures.

Prospective assessment of bone turnover and clinical bone diseases after allogeneic hematopoietic stem-cell transplantation.

BACKGROUND: Bone complications after hematopoietic stem-cell transplantation (HSCT) are relatively frequent. Evaluation of biomarkers of bone turnover and dual energy x-ray absorptiometry (DEXA) are not known in this context. METHODS: We prospectively evaluated bone mineral density, biomarkers of bone turnover, and the cumulative incidence of bone complications after allogeneic HSCT. One hundred forty-six patients were included. Bone mineral density was measured by DEXA 2-month and 1-year post-HSCT. The markers of bone turnover were serum C-telopeptide (C-TP), 5 tartrate-resistant acid phosphatase (bone resorption), and osteocalcin (bone formation) determined pre-HSCT and 2 months and 1 year thereafter. Potential association between osteoporosis at 2 months, osteoporotic fracture or avascular necrosis and, individual patient's characteristics and biologic markers were tested. RESULTS: C-TP was high before and 2 months after transplant. At 2 months, DEXA detected osteoporosis in more than half the patients tested. Male sex, median age less than or equal to 15 years, and abnormal C-TP before HSCT were risk factors significantly associated with osteoporosis. Three-year cumulative incidences of fractures and avascular necrosis were 8% and 11%, respectively. Children were at higher risk of fracture, whereas corticosteroid treatment duration was a significant risk factor for developing a clinical bone complication post-HSCT. Bone complications and osteoporosis are frequent after HSCT. Bone biologic markers and DEXA showed that subclinical bone abnormalities appeared early post-HSCT. CONCLUSION: The risk factors, age, gender, and C-TP easily available at the time of transplantation were identified. Biphosphonates should probably be given to patients with those risk factors.