Low DHEAS: A Sensitive and Specific Screening Test for the Detection of Subclinical Hypercortisolism in Adrenal Incidentalomas

Program: Abstracts - Orals, Poster Previews, and Posters
Session: SAT 379-412-Cushing's Syndrome
Clinical
Saturday, March 7, 2015: 1:00 PM-3:00 PM
Hall D-F, Adrenal (San Diego Convention Center)

Poster Board SAT-392
Michael Conall Dennedy, MD, PhD, MRCPI1, Anand K Annamalai, MD, MRCP2, Olivia Prankerd-Smith1, Andrew S Powlson, MA MB BChir MRCP(UK)2, Johann Graggaber3, Ashley Shaw4, David Halsall, PhD5 and Mark Gurnell, MBBS MA (Med Ed) PhD FRCP6
1Cambridge University & National Institute for Health Research, Cambridge, Cambridge, United Kingdom, 2University of Cambridge, Cambridge, United Kingdom, 3Cambridge University, Cambridge, United Kingdom, 4Cambridge University Hospital NHS Foundation Trust, Cambridge, United Kingdom, 5University of Cambridge & Addenbrooke's hospital, 6University of Cambridge, Metabol, Cambridgeshire, United Kingdom
Context: Subclinical hypercortisolism (SH) occurs in 5-30% of incidentally-detected adrenal adenomas (AIs). Common screening tests for adrenocorticotropin (ACTH)-independent hypercortisolism have significant false positive rates, mandating further investigations that are both time and resource intensive.

Objective: We investigated whether a low basal dehydroepiandrosterone sulphate (DHEAS) level is a sensitive and specific screening test for the detection/exclusion of SH in patients with newly-diagnosed AI.

Patients/methods: 185 consecutive patients with AI referred to our clinic between 2006 and 2013 were screened for clinical and biochemical evidence of adrenal medullary (urinary and plasma metanephrines) and cortical (1 mg dexamethasone suppression test, 24h urinary free cortisol (UFC), serum DHEAS, paired plasma renin and aldosterone) hyperfunction. All positive dexamethasone suppression [>1.8 mcg/dL (50 nmol/L)] and UFC (> upper limit of reference range) results were further investigated, and we diagnosed SH when at least two of the following criteria were met: raised UFC, raised midnight serum cortisol, 48 h dexamethasone suppression test cortisol >1.8 mcg/dL (50 nmol/L). Plasma ACTH was <10 pg/mL (2.2 pmol/L) in all patients with SH.

Results: At presentation, 29 patients (16%) were diagnosed with SH. We calculated an age-and gender-specific DHEAS ratio (derived by dividing measured DHEAS by the lower limit of the respective reference range) for all patients in the cohort and found that a ratio ≤ 1.12 was a sensitive (100%) and specific (91.9%) screening test for the diagnosis of SH. In comparison, a cortisol level after a 1mg dexamethasone suppression test of 1.9 mcg/dL (53 nmol/L) was a sensitive (100%) screening test for SH, but had lower specificity (82.9%). 24 h UFC lacked sensitivity (69%)  and specificity (68%).

Conclusion: A single basal measurement of DHEAS offers comparable sensitivity and greater specificity to the existing gold-standard 1 mg dexamethasone suppression test for the detection of SH in patients with AIs.

Nothing to Disclose: MCD, AKA, OP, ASP, JG, AS, DH, MG

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