Clinical use of biochemical markers of bone remodeling: Current status andfuture directions

Biochemical markers of bone turnover provide a means of evaluating skeletal dynamics that complements static measurements of bone mineral density (BMD ). This review evaluates the use of commercially available bone turnover ma rkers as aids in diagnosis and monitoring response to treatment in patients with osteoporosis. High within-person variability complicates but does not preclude their use. Elevated bone resorption markers appear to be associat ed with increased fracture risk in elderly women, but there is less evidenc e of a relationship between bone formation markers and fracture risk. The c ritical question of predicting fracture efficacy with treatment has not bee n answered. Changes in bone markers as currently determined do not predict BMD response to either bisphosphonates or hormone replacement therapy. Sing le measurements of markers do not predict BMD cross-sectionally (except pos sibly in the very elderly), or change in BMD in individual patients, either treated or untreated. On the other hand, research applications of bone tur nover markers are of value in investigating the pathogenesis and treatment of bone diseases. Markers have potential in the clinical management of oste oporosis, but their use in this regard is not established. Additional studi es with fracture endpoints and information on negative and positive predict ive value are needed to evaluate fully the utility of bone turnover markers in individual patients.