Endocrine Abstracts

Objective: Urinary cortisol and metabolites represents total cortisol production and metabolism. We assayed these metabolites to compared the information that could be extracted compared to the one provided by a sole cortisol assay.

Design and patients: An inexpensive multiplex mass spectrometry assay was set up to quantify cortisol and its metabolites in 43 patients with benign secreting (AT+) or silent (AT−) adrenal tumours compared to 48 lean (Nl) or 143 obese (Ob) subjects, and to 26 patients with a Cushing’s disease (CD). Their routine initial investigation included immunoreactive quantification of urinary free cortisol (UFC).

Results: Cortisol and metabolites were over-excreted in CD but not in Ob subjects. Nl and Ob were thus pooled in a control population (Ctl). Cortisol, tetrahydrocortisol (THF), and tetrahydrocortisone (THE) excretions were significantly increased in AT compared to Ctl subjects whereas immunoreactive UFC was similar. A logistic regression retaining cortisol, THF, and α- and β-cortolone as significant analytes allowed the construction of a receiver-operating characteristics (ROC) curve significantly better than the curve generated by cortisol alone (area under the curve (AUC) 0.927 vs 0.729, respectively, P<0.0001). More importantly, although there was no significant difference between Ctl vs AT− subjects for cortisol or metabolites a logistic regression retaining cortisol, alloTHF, and α- and β-cortolone as significant analytes generated a ROC curve performing significantly better than cortisol alone (AUC 0.910 vs 0.635, respectively, P<0.0001).

Conclusion: Cortisol and metabolites excretion is modified in AT, including AT−, patients even without modification of UFC. Clinical usefulness of these biomarkers has to be investigated in prospective studies following-up patients with AT.