Screening for Cushing's syndrome in obese patients

ABSTRACT

Objectives: The aim of this study was to examine the frequency of Cushing's syndrome (CS) in obese patients devoid of specific clinical symptoms of Cushing's syndrome. Methods: A total of 150 obese patients (129 female, 21 male; mean age 44.41 ± 13.34 yr; mean BMI 35.76 ± 7.13) were included in the study. As a first screening step, we measured 24-h urinary free cortisol (UFC). An overnight 1-mg dexamethasone suppression test was also performed on all patients. Urinary free cortisol levels above 100 ìg/24 h were considered to be abnormal. Suppression of serum cortisol <1.8 ìg/dL after administration of 1 mg dexamethasone was the cut-off point for normal suppression. The suppression of the serum cortisol levels failed in all of the patients. Results: Measured laboratory values were as follows ACTH, median level 28 pg/ml, interquartile range (IQR) 14-59 pg/ml; fasting glucose, 100 (91-113) mg/dL; insulin, 15.7 (7.57-24.45) mU/ml; fT4, 1.17 (1.05-1.4) ng/dL; TSH, 1.70 (0.91-2.90) mIU/L; total cholesterol, 209 (170.5-250) mg/dL; LDL-c, 136 (97.7-163) mg/dL; HDL-c, 44 (37.25-50.75) mg/dL; VLDL-c, 24 (17-36) mg/dL; triglycerides, 120.5 (86-165) mg/dL. The median UFC level of the patients was 30 ìg/24 h (IQR 16-103). High levels of UFC (>100 ìg/24 h) were recorded in 37 patients (24 percent). Cushing's syndrome was diagnosed in 14 of the 150 patients (9.33 percent). Etiologic reasons for Cushing's syndrome were pituitary microadenoma (9 patients), adrenocortical adenoma (3 patients), and adrenocortical carcinoma (1 patient). Conclusion: A significant proportion (9.33 percent) of patients with simple obesity were found to have Cushing's syndrome. These findings argue that obese patients should be routinely screened for Cushing's syndrome.