Thursday, September 3, 2009

Late-night and low-dose dexamethasone-suppressed cortisol in saliva and serum for the diagnosis of cortisol-secreting adrenal adenomas

Timo Deutschbein, Nicole Unger, Jakob Hinrichs, Martin Walz, Klaus Mann and Stephan Petersenn

T Deutschbein, Department of Endocrinology, Medical Center, University of Duisburg-Essen, Essen, Germany
N Unger, Department of Endocrinology and Division of Laboratory Research, Medical Center, University of Duisburg-Essen, Essen, Germany
J Hinrichs, Department of Surgery and Center of Minimally Invasive Surgery, Kliniken Essen-Mitte, Essen, Germany
M Walz, Department of Surgery and Center of Minimally Invasive Surgery, Kliniken Essen-Mitte, Essen, Germany
K Mann, Department of Endocrinology and Division of Laboratory Research, Medical Center, University of Duisburg-Essen, Essen, Germany
S Petersenn, Department of Endocrinology and Division of Laboratory Research, Medical Center, University of Duisburg-Essen, Essen, Germany

Correspondence: Timo Deutschbein, Email: timo.deutschbein@uni-due.de

Objective: In patients with adrenal incidentalomas, hormonally active masses need to be considered, particularly cortisol-producing adenomas (CPA), aldosterone-producing adenomas, and pheochromocytomas. The screening for hypercortisolism relies on confirming excess cortisol secretion and insufficient suppression after dexamethasone. Because of its high correlation with free cortisol and its stress-free collection, salivary cortisol (SaC) may offer advantages over serum cortisol (SeC). We evaluated the value of SaC and SeC for the diagnosis of CPA.

Design: Comparative study between 2001 and 2006.

Methods: Thirty-eight patients with confirmed CPA were compared to 18 healthy subjects as well as 48 control patients suffering from aldosterone-producing adenomas (n=13), pheochromocytomas (n=16), or non-functioning adenomas (n=19). Sampling of saliva and serum was performed at 2300h and at 0800h following low-dose dexamethasone suppression. ROC analysis was used to calculate thresholds with at least 95% sensitivity for CPA.

Results. Regarding the cutoffs for late-night cortisol, SaC (4.8 nmol/l, sensitivity 97%, specificity 69%) was slightly more specific than SeC (115 nmol/l, sensitivity 97%, specificity 63%). In contrast, the cutoff for dexamethasone-suppressed SaC (3.7 nmol/l, sensitivity 97%, specificity 83%) was slightly less specific than SeC (94 nmol/l, sensitivity 97%, specificity 88%). However, the latter cutoffs demonstrated greater specificity when compared with the cutoffs for late-night cortisol.

Conclusion. The diagnostic accuracy of SaC is as good as SeC. Due to its higher specificity, dexamethasone-suppressed cortisol is preferable to late-night cortisol when screening for Cushing’s syndrome in patients with adrenal incidentalomas.

from http://www.eje.org/cgi/content/abstract/EJE-09-0517v1