Comparison of heel ultrasound and finger DXA to central DXA in the detection of osteoporosis. Implications for patient management.

The goal of the study was to investigate the potential discordance in patient management when a clinician assumes that a peripheral device is a diagnostic surrogate for central DXA in the detection and treatment of osteoporosis. Over a period of 2 mo, asymptomatic women seeking conventional central DXA evaluation for osteoporosis at a diagnostic imaging center were also evaluated with heel ultrasound and finger DXA peripheral imaging devices. T-Scores of -2.5 or less in screening examinations were used to evaluate the discordance between the two peripheral devices and central DXA in the identification of patients with osteoporosis. Higher T-score cutoffs (>-2.5) were also evaluated. Using central DXA as the standard for comparison, the sensitivity of heel ultrasound for screening cases was 0.34 and specificity was 0.92. For finger DXA, sensitivity was 0.23 and specificity was 0.92. Overall discordance between the peripheral devices and central DXA was 21% (heel) and 23% (finger). Heel ultrasound identified 7 out of every 22 osteoporotic patients diagnosed with central DXA. Finger DXA identified 5 out of every 22 osteoporotic patients. Using lower T-scores for the peripheral devices increased sensitivity but markedly increased discordance with DXA. The peripheral devices we studied cannot be considered equivalent surrogates for central DXA in the screening of asymptomatic women for osteoporosis.