Bone Mineral Density, Prevalence of Vertebral Fractures, and Bone Quality in Patients with Adrenal Incidentalomas with and without Subclinical Hypercortisolism: An Italian Multicenter Study

Abstract

In patients with adrenal incidentalomas and subclinical hypercortisolism (SH), the factors influencing bone and the prevalence of vertebral fractures are debated. Spinal deformity index (SDI), which reflects bone quality, has never been evaluated. The objective of the study was to investigate in these patients SDI and factors influencing the prevalence of fractures. This was a retrospective, multicenter study. The study was conducted on an in- and outpatient basis. Patients included 287 adrenal incidentaloma patients (111 eugonadal males, 31 premenopausal, 145 postmenopausal females) and 194 controls (90 eugonadal males, 29 premenopausal, 75 postmenopausal females). Bone mineral density (BMD) was measured by dual X-ray absorptiometry at lumbar spine and femoral neck. By radiograph each vertebra was assessed as intact (grade 0) or grade 1 (20-25%), 2 (25-40%), or 3 (>40%) deformity; SDI was calculated by summing the grade of deformity for each vertebra. SH was diagnosed in the presence of at least two of the following: urinary free cortisol greater than 70 microg per 24 h (193.1 nmol/liter), cortisol after 1-mg dexamethasone test greater than 3.0 microg/dl (>82.8 nmol/liter), ACTH less than 10 pg/ml (<2.2 pmol/liter). BMD was significantly lower in SH+ than SH- patients and controls (lumbar spine -0.73 +/- 1.43, 0.17 +/- 1.33, 0.12 +/- 1.21, respectively; femoral neck -0.37 +/- 1.06, 0.07 +/- 1.09, 0.17 +/- 1.02). Patients with SH had higher fracture prevalence and SDI than those without SH and controls (70.6, 22.2, 21.8%, respectively, P < 0.0001; 0.31 +/- 0.68, 0.39 +/- 0.93, 1.35 +/- 1.27, respectively, P < 0.0001). Fractures and SDI were associated with SH (odds ratio 7.27, 95% confidence interval 3.94-13.41, P = 0.0001; beta = 0.352, t = 6.241, P = 0.0001, respectively) regardless of age, BMD, menopause, and gender. SH is associated with low BMD, high fracture prevalence, and reduced bone quality as measured by SDI.