Comparison of bone mineral density of the phalanges, lumbar spine, hip, and forearm for assessment of osteoporosis in postmenopausal women

The objective of this study was to compare peripheral bone mineral density (BMD) of the phalanges with BMD of the lumbar spine, total hip, femoral nec k, and forearm and to determine the clinical value of measuring a single pe ripheral site (phalanges) in identifying postmenopausal women with osteopor osis. BMD was measured by dual-energy X-ray absorptiometry using the accuDE XA(R) (ADXA-finger) (Schick, New York, NY) and the QDR-4500 (DXA-lumbar spi ne, hip, forearm) (Hologic, Waltham, MA). Correlation coefficients between ADXA and DXA of the lumbar spine, total hip, femoral neck, and one third ra dial site ranged from 0.53 to 0.73. The sensitivity of an ADXA T-score of - 2.5 in identifying patients with a DXA T-score of less than or equal to -2. 5 at the femoral neck was 35%. An ADXA T-score cut point of -1.0 improved t he sensitivity of ADXA in identifying patients with a femoral neck T-score of less than or equal to -2.5 (85%). but the specificity declined from 88 t o 49%. There was substantial discordance in the diagnosis of osteoporosis w hen a single site was measured, regardless of technique. Within the limitat ions of single-site measurements, BMD measured by ADXA has adequate sensiti vity to identify women with low BMD at the femoral neck, if an appropriate T-score criterion is used.