Progressively increased patterns of subclinical cortisol hypersecretion in adrenal incidentalomas differently predict major metabolic and cardiovascular outcomes: a large cross-sectional study

Background: Subclinical Cushing's syndrome (SCS) is defined as alterations in hypothalamic-pituitary-adrenal axis without classic signs/symptoms of glucocorticoid excess. Whether SCS leads to metabolic and cardiovascular diseases is still controversial. Aim: To evaluate the prevalence of hypertension, type 2 diabetes (T2D), coronary heart disease (CHD), ischemic stroke, osteoporosis, and fractures, and their relationship to increasing patterns of subclinical hypercortisolism, in patients with nonsecreting adrenal adenomas (NSA) and SCS. Methods: Using the 1 mg dexamethasone suppression test (DST), 348 patients were classified as follows: 203 were defined as NSA and 19 SCS, using the most stringent cutoff values (! 50 and >138 nmol/l respectively). Patients with cortisol post-DST (50-138 nmol/l) were considered as intermediate phenotypes and classified as minor (n=71) and major (n=55) using plasma ACTH and/or urinary free cortisol as additional diagnostic tools. Results: SCS patients showed higher prevalence of T2D, CHD, osteoporosis, and fractures with respect to NSA. Intermediate phenotypes also showed higher prevalence of CHD and T2D with respect to NSA. The prevalence of all clinical outcomes was not different between intermediate phenotype patients, which were therefore considered as a single group (IP) for multivariate logistic regression analysis: both IP and SCS-secreting patterns showed a significant association with CHD (odds ratio (OR), 4.09; 95% confidence interval (CI), 1.47-11.38 and OR, 6.10; 95% CI, 1.41-26.49 respectively), independently of other potential risk factors. SCS was also independently associated with osteoporosis (OR, 5.94; 95% CI, 1.79-19.68). Conclusions: Patterns of increasing subclinical hypercortisolism in adrenal adenomas are associated with increased prevalence of adverse metabolic and cardiovascular outcomes, independently of other potential risk factors.