1. The diagnostic accuracy of increased late night salivary cortisol for Cushing's syndrome: a real-life prospective study.
- Author
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Ceccato F, Marcelli G, Martino M, Concettoni C, Brugia M, Trementino L, Michetti G, and Arnaldi G
- Subjects
- Adult, Aged, Case-Control Studies, Cushing Syndrome metabolism, Female, Follow-Up Studies, Humans, Male, Middle Aged, Prognosis, Prospective Studies, Young Adult, Biomarkers metabolism, Circadian Rhythm, Cushing Syndrome diagnosis, Hydrocortisone metabolism, Saliva metabolism
- Abstract
Introduction and Aim: A prompt diagnosis of Cushing's Syndrome (CS) in high-risk populations is mandatory: 1-mg dexamethasone suppression test (1-mg DST), late night salivary cortisol (LNSC), and urinary-free cortisol (UFC) are recommended, despite thresholds calculated in retrospective studies. Our aim was to study the diagnostic accuracy of LNSC measured with chemiluminescence assay in a prospective study, confirming discrepancies with mass spectrometry (MS)., Materials and Methods: We enrolled 117 controls and 164 suspected CS (CS = 47, non-CS = 117). In case of increased LNSC, high clinical suspicion of CS or adrenal incidentaloma, patients were hospitalized to exclude/confirm CS., Results: LNSC levels were higher in patients with suspected CS, CS, and non-CS than controls. Considering 16 nmol/L as threshold for CS, overall LNSC revealed SE 97% and SP 84% in the whole group of subjects considered, achieving positive/negative likelihood ratio of 5.56/0.045, respectively. 35 out of 81 subjects with increased LNSC were non-CS (15 diabetic and 20 obese): considering only those patients with increased likelihood to have a CS (the non-CS patients) SP decreased to 70%, and further reduced to 60% if we discharged subjects with adrenal incidentaloma. MS analyses reduced partially the number of false-positive LNSC., Conclusions: LNSC measured in automated chemiluminescence is reliable in clinical practice: it present a high diagnostic accuracy to exclude hypercortisolism in patients with normal cortisol levels. MS could be used to reduce the number of false-positive results; nevertheless, some non-CS subjects with functional hypercortisolism could have a mild impairment of cortisol rhythm.
- Published
- 2019
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