[Detection of preclinical Cushing's syndrome in overweight type 2 diabetic patients]

Preclinical Cushing's syndrome (PCS) is a condition in which cortisol excess is not associated to clinical features of Cushing's syndrome. The aim of this study was to detect PCS in 48 ambulatory overweight type 2 diabetic patients (DM). Controls were 40 normoglycemic obese (Ob) and 36 normo-weight healthy subjects (N). In DM (47/48) total urinary cortisol (UF) levels were similar to those found in Ob and N. Evening urinary cortisol (Spot F) was significantly higher than either Ob (p: 0.0001) or N (p: 0.03), although values did not overcome the upper normal limit (44 ng/mg creatinine). False positive results to the overnight 1 mg dexamethasone suppression test were found in 31% and 22% of DM and Ob, respectively. In a DM female an elevated UF and Spot F associated to absence of cortisol inhibition to the overnight 1 mg dexamethasone suppression test was repeatedly detected. Diagnosis of PCS was performed. Remission of hypercorticism and glycemic control were achieved after pituitary surgery. It would be useful to screen DM patients with poor glycemic control for PCS.