Specificity of Screening Tests for Cushing’s Syndrome in an Overweight and Obese Population

• Published in: The journal of clinical endocrinology and metabolism Vol. 94; no. 10; pp. 3857 - 3864
• Main Authors: Baid, Smita K., Rubino, Domenica, Sinaii, Ninet, Ramsey, Sheila, Frank, Arthur, Nieman, Lynnette K.
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Oxford University Press 01.10.2009; Endocrine Society; The Endocrine Society
• Subjects: Adrenals. Adrenal axis. Renin-angiotensin system (diseases); Adrenocorticotropic hormone; Adult; Aged; Biological and medical sciences; Biomarkers - metabolism; Body weight; Confounding Factors, Epidemiologic; Cortisol; Cross-Sectional Studies; Cushing Syndrome - diagnosis; Dexamethasone; Dexamethasone - metabolism; Diabetes mellitus; Diagnosis, Differential; Endocrinopathies; False Positive Reactions; Feeding. Feeding behavior; Female; Fundamental and applied biological sciences. Psychology; Hormones; Humans; Hydrocortisone - metabolism; Hydrocortisone - urine; Liquid chromatography; Male; Mass Screening - methods; Mass Screening - standards; Mass spectroscopy; Medical sciences; Middle Aged; Nervous system diseases; Non tumoral diseases. Target tissue resistance. Benign neoplasms; Obesity; Obesity - complications; Original; Overweight; Overweight - complications; Overweight - diagnosis; Pituitary; Population studies; Prevalence; Prospective Studies; Saliva - metabolism; Sensitivity and Specificity; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Vertebrates: endocrinology; Young Adult; Endocrinopathy; Human; Obesity; Adrenal cortex diseases; Nutrition; Body weight; Nutrition disorder; Cushing syndrome; Metabolic diseases; Corporal biometry; Hyperadrenocorticism; Medical screening; Overweight; Specificity; Adrenal gland diseases; Population; Endocrinology; Nutritional status
• DOI: 10.1210/jc.2008-2766
• ISSN: 0021-972X; 1945-7197

Context: Recent reports suggest a higher prevalence (1–5%) of Cushing’s syndrome in certain patient populations with features of the disorder (e.g., diabetes), but the prevalence in the overweight and obese population is not known. Objective: The aim of the study was to evaluate the diagnostic performance of screening tests for Cushing’s syndrome in overweight and obese subjects with at least two other features of the disorder. Design and Setting: We conducted a cross-sectional prospective study. Subjects and Methods: A total of 369 subjects (73% female) completed two or three tests: a 24-h urine cortisol, and/or late-night salivary cortisol, and/or 1 mg dexamethasone suppression test (DST). If any result was abnormal [based on laboratory reference range or cortisol after DST ≥1.8 μg/dl (50 nmol/liter)], tests were repeated and/or a dexamethasone-CRH test was performed. Subjects with abnormal DST results and a low dexamethasone level were asked to repeat the test with 2 mg of dexamethasone. Results: In addition to obesity, subjects had a mean of five to six features of Cushing’s syndrome. None was found to have Cushing’s syndrome. Test specificities to exclude Cushing’s syndrome for subjects who completed three tests were: urine cortisol, 96% [95% confidence interval (CI), 93–98%]; DST, 90% (95% CI, 87–93%); salivary cortisol, 84% by RIA (95% CI, 79–89%) and 92% by liquid chromatography-tandem mass spectrometry (95% CI, 88–95%). The combined specificity (both tests normal) for all combinations of two tests was 84 to 90%, with overlapping CIs. Conclusion: These data do not support widespread screening of overweight and obese subjects for Cushing’s syndrome; test results for such patients may be falsely abnormal.Data from this study does not support widespread screening of overweight and obese subjects for Cushing’s syndrome.