Subclinical hypercortisolism among outpatients referred for osteoporosis

Hypercortisolism is known to cause osteoporosis.

To evaluate the prevalence of subclinical hypercortisolism in participants referred for evaluation of osteoporosis.

Cross-sectional study.

Two community hospitals and research institutes in Italy.

219 patients without clinically overt hypercortisolism or other secondary causes of osteoporosis who were referred for evaluation of osteoporosis between January 2005 and December 2005.

Bone mineral density was measured by using dual-energy x-ray absorptiometry, and hypercortisolism was assessed with serum cortisol levels after a dexamethasone suppression test. Also measured were 24-hour urinary free cortisol levels and midnight plasma cortisol levels.

Seven of 65 patients with T-scores of 2.5 or less and vertebral fractures had subclinical hypercortisolism (prevalence, 10.8% [95% CI, 3.23% to 18.31%]). This prevalence was 4.8% (CI, 1.32% to 8.20%) among patients with osteoporosis. In multivariable analyses adjusted for age, sex, and body mass index, a positive dexamethasone suppression test result was associated with the presence of osteoporosis (odds ratio, 3.37 [CI, 1.78 to 6.43]; P < 0.001) and vertebral fractures (odds ratio, 1.70 [CI, 1.04 to 2.79]; P = 0.035).

The study was conducted in a referral setting; its findings may not apply to the general population.

Subclinical hypercortisolism may be more common than is generally recognized in patients with osteoporosis in whom secondary causes of osteoporosis have been excluded.