title: Bone turnover markers: understanding their value in clinical trials and clinical practice.
abstract: While bone mineral density (BMD) by dual-energy X-ray absorptiometry is the primary method of determining fracture risk, assessing bone turnover may add valuable information for the management of patients with low bone mass. Bone turnover markers (BTMs) are used in clinical trials where they can provide essential information on the biological efficacy of osteoporosis treatments. In such population-based studies, BTMs can predict fracture risk independent of BMD. When combined with BMD, they improve the fracture risk estimate above and beyond BMD alone in postmenopausal osteoporotic women. Since changes in bone turnover after the initiation of therapy with bone resorption inhibitors occur much more rapidly than changes in BMD, treatment efficacy could, in theory, be determined within weeks of using BTMs. However, such predictive value is limited by the large biological variability of these biochemical markers, even though newer automated methods have reduced their analytical variability. Consequently, widespread adoption as a means of predicting treatment efficacy in fracture prevention for individual patients cannot yet be recommended. BTMs may be useful for monitoring adherence to antiresorptive therapy and may aid in identifying patients for whom antiresorptive therapy is most appropriate. Thus, although BTMs are currently confined to clinical research applications, further improvement in assay precision may extend their diagnostic value in clinical settings.
authors.affiliation: Division of Bone and Mineral Diseases, Department of Internal Medicine, Washington University School of Medicine, 660 S. Euclid Ave., PO Box 8301, St. Louis, MO 63110, USA. rcivitel@dom.wustl.edu
authors.forename: R
authors.initials: R
authors.lastname: Civitelli
authors.forename: R
authors.initials: R
authors.lastname: Armamento-Villareal
authors.forename: N
authors.initials: N
authors.lastname: Napoli
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D000469:Alkaline Phosphatase / Q000032:analysis*; D015415:Biomarkers / Q000032:analysis; D015519:Bone Density; D016723:Bone Remodeling / Q000502:physiology*; D002986:Clinical Trials as Topic; D005260:Female; D050723:Fractures, Bone / Q000175:diagnosis*; D006801:Humans; D008875:Middle Aged; D015675:Osteocalcin / Q000032:analysis*; D010024:Osteoporosis / Q000175:diagnosis* / Q000188:drug therapy; D018570:Risk Assessment
chemical_list: D015415:Biomarkers; D015675:Osteocalcin; D000469:Alkaline Phosphatase