Screening for Cushing's syndrome in patients with morbid obesity and type 2 diabetes before bariatric surgery

BACKGROUND: Bariatric surgery is the most effective treatment for morbid obesity and type 2 diabetes. Hypercortisolism in patients undergoing bariatric surgery may reduce the effectiveness of surgery and increase the risk of complications. 

AIM: To assess the prevalence and clinical forms of hypercortisolism in patients with morbid obesity and type 2 diabetes mellitus undergoing examination before bariatric interventions.

MATERIALS AND METHODS: Screening for Cushing's syndrome was performed in patients with morbid obesity and type 2 diabetes mellitus referred to the clinic for examination before bariatric surgery. The overnight dexamethasone suppressive test with 1 mg dexamethasone (1-mg DST) was used as a first-line test. Additional tests included 24-hour urinary free cortisol excretion and evening cortisol level in saliva or blood serum. In case of pathological results of the second-line tests, the ACTH level was measured, and suppressive test with 8 mg dexamethasone was performed.

RESULTS: The study included 91 patients, 21 men and 70 women, aged 27 to 66 years. A decrease in the cortisol level <50 nmol/l in the 1-mg DST was recorded in 75 patients. In the remaining subjects, the cortisol concentration exceeded the cutoff point, which required further tests. In 14 patients (15.4%) with functional hypercortisolism (pseudo-Cushing`s syndrome), the cortisol level in 1-mg DST ranged from 50 to 140 nmol/l (median 67.7). In three women, the cortisol level in the 1-mg DST demonstrated very high values (593, 461 and 425 nmol/l). During further examination, pituitary adenomas were verified in two of them, and the third woman was diagnosed with adenomas in both adrenal glands.

CONCLUSION: The obtained results confirm the need for screening for hypercortisolism in all patients with morbid obesity and type 2 diabetes scheduled for bariatric surgery.

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