Endocrine Abstracts

Background: Subclinical Cushing’s syndrome (SCS) is defined as alterations in hypothalamic–pituitary–adrenal axis without classic signs or symptoms of glucocorticoid excess. This condition has been associated to increased risk of adverse metabolic and cardiovascular outcomes, independently of other potential risk factors. However, is still not known if this condition could lead to a higher mortality respect to non-secreting adrenal masses (NSA).

Aim: To evaluate the overall mortality of long-term follow-up patients with NSA, intermediate phenotypes of subclinical hypercortisolism (minor–ImP and major–IMP), and SCS.

Methods: This study involved 167 subjects. None of the patients underwent to surgical treatment of the adrenal mass. According to our previous study, the 1-mg dexamethasone suppression test (DST) was used as primary diagnostic tool, and patients were classified as below: 110 were defined NSA and 4 SCS, using the most stringent cut-off values (<50 nmol/l and >138 nmol/l respectively). Of the 53 patients with cortisol post-DST between 50 and 138 nmol/l, 29 were defined ImP and 24 IMP, using plasma ACTH and/or urinary free cortisol as additional diagnostic tools. Mean duration of follow-up was 8.8 years.

Results: Patients age was different in the four groups (P=0,001). Mortality analysis was then performed by Cox regression, using age as covariate. The overall unadjusted hazard ratios were 2.80, 3.82, and 7.70 in ImP (P=0.015), IMP (P=0.003), and SCS (P=0.008), respectively. The hazard ratios adjusted for age were 3.22 and 5.53 in IMP (P=0.010) and SCS (P=0.026), respectively, when compared to the NSA group. No significance was found for ImP patients after adjustment for age.

Conclusion: Increasing patterns of subclinical cortisol hypersecretion are associated with increased overall mortality, independently of the effect of age. Further analysis are needed to increase the study population with data from medium-term follow-up.