Diagnostic challenges in osteoporosis - Indications for bone densitometry and establishing secondary causes

OBJECTIVE To review indications for assessing bone mineral density (BMD) an d to review patient characteristics and diseases associated with osteoporos is. QUALITY OF EVIDENCE This paper is based on data from longitudinal observati onal studies of how BMD and other risk factors affect development of fragil ity fractures and on several peer-reviewed publications describing pathophy siology of bone turnover and pathogenesis of osteoporosis. Indications for obtaining BMD and monitoring treatment are based on the recommendations of the Osteoporosis Society of Canada derived from the consensus opinion of a panel of experts in osteoporosis and based on their review of the primary l iterature. MAIN MESSAGE Measurement of BMD provides the best single objective predicto r of the relative risk of fracture at sites such as the vertebrae, hip, and wrist, predicting the likelihood of fracture with as much accuracy as meas urement of elevated blood pressure predicts stroke. In addition to making t he diagnosis of osteoporosis, BMD measurements are used to monitor progress ion of osteoporosis and effects of therapy. At this date, dual energy x-ray absorptiometry is preferred for measuring BMD. The most likely causes of o steoporosis in any patient are age, hormone withdrawal (in both men and wom en), and drugs (particularly corticosteroids). Secondary causes. particular ly hyperparathyroidism and multiple myeloma, should be excluded by performi ng appropriate laboratory tests. CONCLUSION A BMD measurement should be obtained for patients at high risk o f osteoporosis and fragility fractures to guide initiation and monitor succ ess of therapy.