Saliva versus serum cortisol to identify subclinical hypercortisolism in adrenal incidentalomas: simplicity versus accuracy

• Published in: Journal of endocrinological investigation Vol. 42; no. 12; pp. 1435 - 1442
• Main Authors: Vieira-Correa, M., Giorgi, R. B., Oliveira, K. C., Hayashi, L. F., Costa-Barbosa, F. A., Kater, C. E.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.12.2019; Springer Nature B.V
• Subjects: Adrenal Gland Neoplasms - complications; Adrenal Gland Neoplasms - metabolism; Adrenocorticotropic hormone; Adult; Aged; Aged, 80 and over; Autonomy; Cardiovascular diseases; Cortisol; Cushing syndrome; Cushing Syndrome - diagnosis; Cushing Syndrome - etiology; Cushing Syndrome - metabolism; Dexamethasone; Endocrinology; Female; Hormones; Humans; Hydrocortisone - analysis; Hydrocortisone - blood; Incidental Findings; Internal Medicine; Male; Medicine; Medicine & Public Health; Metabolic Diseases; Metabolism; Middle Aged; Nervous system diseases; Original Article; Pituitary; Pituitary-Adrenal Function Tests; Retrospective Studies; Saliva; Saliva - chemistry; Sensitivity and Specificity; Young Adult; Dexamethasone suppression; Subclinical hypercortisolism; Saliva cortisol; Adrenal incidentaloma
• ISSN: 1720-8386; 0391-4097; 1720-8386
• DOI: 10.1007/s40618-019-01104-8

Purpose Subclinical hypercortisolism (SCH) leads to metabolic derangements and increased cardiovascular risk. Cortisol autonomy is defined by the overnight 1 mg dexamethasone suppression test (DST). Saliva cortisol is an easier, stress-free, and cost-effective alternative to serum cortisol. We compared 23 h and post-1 mg DST saliva with serum cortisol to identify SCH in adrenal incidentalomas (AI). Methods We analyzed 359 DST obtained retrospectively from 226 AI subjects (173F/53 M; 19–83 years) for saliva and serum cortisol. We used three post-DST serum cortisol cutoffs to uncover SCH: 1.8, 2.5, and 5.0 μg/dL. We determined post-DST and 23 h saliva cortisol cutoffs by ROC curve analysis and calculated their sensitivities (S) and specificities (E). Results The sensitive 1.8 μg/dL cutoff defined 137 SCH and 180 non-functioning adenomas (NFA): post-DST and 23 h saliva cortisol S/E were: 75.2%/74.4% and 59.5%/65.9%, respectively. Using the specific 5.0 μg/dL cortisol cutoff (22 SCH/295 NFA), post-DST and 23 h saliva cortisol S/E were 86.4%/83.4% and 66.7%/80.4%, respectively. Using the intermediate 2.5 μg/dL cutoff (89 SCH/228 NFA), post-DST and 23 h saliva cortisol S/E were 80.9%/68.9% and 65.5%/62.8%, respectively. Conclusion Saliva cortisol showed acceptable performance only with the 5.0 μg/dL cortisol cutoff, as in overt Cushing’s syndrome. Lower cutoffs (1.8 and 2.5 μg/dL) that identify larger samples of patients with poor metabolic outcomes are less accurate for screening. These results may be attributed to pre-analytical factors and inherent patient conditions. Thus, saliva cortisol cannot replace serum cortisol to identify SCH among patients with AI for screening DST.