Quantitative ultrasound technology in evaluating bone status and osteoporosis in patients with Cushing's syndrome

Osteoporosis is a major feature of Cushing's syndrome (CS), and fragility fractures may be the first sign of the disease. The aim of this study was to evaluate the ability of quantitative ultrasound technology (QUS) in diagnosing osteoporosis in patients with CS. Sixty-three consecutive patients (mean age 38.6 +/- 13.0 years), 13 (20.6%) men and 50 (79.4%) women, with confirmed CS underwent both dual-energy X-ray densitometry (DXA) and QUS. Two groups of patients were selected: group A, 23 patients, T-score -2 SD or less (bone mineral density [BMD] femoral neck < or = 695 g/cm(2)), and group B, 40 patients, T-score above -2 SD. Age (42 +/- 12 vs. 37 +/- 13 years) and 24-h free urinary cortisol (499 +/- 345 vs. 469 +/- 319 microg/day) did not differ significantly (P = NS) between groups, while the body mass index did (24.3 +/- 4.1 vs. 28.1 +/- 4.6, P = 0.002). Unlike DXA, QUS values did not differ significantly (P = NS) between groups. Moreover, in the overall population, as well as in a single group, there was no correlation (R < 0.5, P = NS) between QUS and DXA parameters. In conclusion, in our study QUS was not able to differentiate osteoporotic patients from those with normal BMD measured by DXA, and thus QUS technology should not be used to discriminate between osteopenic and nonosteopenic patients with CS.