Use of the desmopressin test in the differential diagnosis of pseudo-Cushing state from Cushing's disease.

Context: The desmopressin (DDAVP) test has been proposed to discriminate Cushing’s disease (CD) from pseudo-Cushing states (PC); however, current information on its value is scarce and contradictory. Objective: The aim of the study was to assess the ability of the DDAVP test in distinguishing between these conditions, with emphasis on subjects with mild hypercortisolism. Design and Setting: We conducted a retrospective/prospective study at the Division of Endocrinology, Polytechnic University of Marche, Ancona, Italy. Patients: The study included 52 subjects with CD, 28 with PC, and 31 control subjects (CT). Intervention(s): We performed the DDAVP test and standard diagnostic procedures for the diagnosis of Cushing’s syndrome. Main Outcome Measure(s): The diagnosis/exclusion of CD was measured. Results: Interpretation of the DDAVP test based on percentage and absolute increment of cortisol and ACTH did not afford acceptable values of both sensitivity (SE) and specificity (SP). CD diagnosis based on simult...