Cushing’s syndrome in a clinic population with diabetes

Abstract

Background: A recent report has suggested that occult Cushing’s syndrome (CS) may be present in a significant number of patients with type 2 diabetes mellitus. The aim of this study was to determine whether any patients in our clinic population with diabetes had this condition. Methods: One hundred and seventy‐one consecutive overweight attendees at the diabetic clinic were enrolled in a study to assess the presence of occult CS. The initial screen was with the 1 mg overnight dexamethasone suppression test and follow‐up testing, where indicated was with a 24 h collection for urine‐free cortisol. Results: Thirty‐one of 171 patients had a positive result from the overnight dexamethasone suppression test. Follow‐up testing with 24 h urine‐free cortisol reduced the number of patients with positive results to 3. Two of these were shown to have alcoholic pseudo‐CS. The third patient has had several high urine‐free cortisol results, in the presence of normal scans of pituitary and adrenals. He has no stigmata of CS and is being observed. Conclusion: Based on the results of our study, there would appear to be little value in screening type 2 diabetics for CS, in the absence of clinical suspicion.