Bone loss determined by quantitative ultrasonometry correlates inversely with disease activity in patients with endogenous glucocorticoid excess due to adrenal mass

Objective: Glucocorticoid excess is widely recognized as one of the most im portant causes of bone loss. The mechanism of glucocorticoid-induced osteop orosis is presumably multifactorial, and consists of the loss of organic an d non-organic compounds. Efforts have been made to develop simple physical methods for the assessment of bone tissue for the screening of subjects at high risk of osteoporosis, without the use of radioactive sources or ionizi ng radiation. Quantitative ultrasonometry (QUS) has been suggested as a use ful method for monitoring patients undergoing glucocorticoid therapy, which is the most common cause of glucocorticoid excess. QUS appears to detect m ore structural bone changes than the traditional methods and allows assessm ent of bone density and elasticity, both characteristics influenced by orga nic and non-organic bone compounds. However, the use of QUS has not yet bee n extensively investigated in subjects with endogenous cortisol excess. The aim of this study was to evaluate the usefulness and predictive power of Q US in assessing bone loss in subjects with differing degrees of endogenous cortisol excess due to adrenal mass. Design: Thirty-four patients (20 women and 14 men) aged between 21 and 59 y ears were evaluated; fifteen (9 women and 6 men; median age, 42 years) were affected by overt Cushing's syndrome (CS) and nineteen (11 women and 8 men ; median age, 44 years) by subclinical CS, defined as lacking clinical sign s of hormone excess despite the presence of at least two abnormalities in h ypothalamic-pituitary-adrenal axis function, as assessed by routine endocri ne tests. All women included were eumenorrhoic. Methods: QUS measurement of amplitude-dependent speed of sound was performe d on the 2nd to 5th proximal phalanges of the non-dominant hand using a DBM Sonic 1200R bone profiler (Igea S.r.l, Italy). The results were compared w ith bone density assessed on lumbar vertebrae (L1-L4) and femoral neck site s by dual-energy X-ray absorptiometry (DEXA). Results: A strongly significant bone loss was detected by finger QUS measur ement when the patients were considered either all together or as two subgr oups (P < 0.001, all). The bone density decrease in the fingers was similar to that found at the lumbar spine and femoral neck by the DEXA technique. Lumbar and finger Z-scores correlated inversely with 24 h urinary free cort isol (UFF) excretion (P < 0.01, both). Finger Z-scores also correlated inve rsely with the estimated duration of subclinical CS (P < 0.05). Concerning disease activity, only UFF was confirmed by multivariate analysis to be an independent factor influencing bone loss (P < 0.05). A positive correlation between the results of the two techniques was found in controls (P < 0.05) but not in patients, The lack of correlation between the two techniques in patients can probably be attributed to the different parameters of bone al teration measured by the techniques. Conclusions: The detection of bone loss in subclinical CS similar to that i n overt CS suggests that all subjects with endogenous cortisol excess shoul d be evaluated for bone mass. QUS measurement appears to be a reliable, rad iation-free, simple and fast tool for the identification of bone alteration in subjects with endogenous cortisol excess.