Differential diagnosis of Cushing's Syndrome versus pseudo-Cushing

• Grant number: 15/12531-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date until: September 01, 2015
• End date until: February 28, 2017
• Field of knowledge: Health Sciences - Medicine - Medical Clinics
• Principal Investigator: Vania dos Santos Nunes Nogueira
• Grantee: Marcos Vinícius Gama Cabral
• Host Institution: Faculdade de Medicina (FMB). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

Faced with the clinical need and the diagnostic difficulty in distinguishing the pseudo-Cushing's syndrome and Cushing's syndrome, several studies have proposed diagnostic tests with 10 g of desmopressin intravenously (IV), corticotrophic plasma hormone and serum cortisol being measured on standardized times for each study. However, there is controversy about the accuracy of these tests and what values would be used to consider a diagnosis or another. To establish this differential diagnosis, this research aims to perform a systematic review of the accuracy of the desmopressin (DDAVP) test at a dose of 10 ug IV to differentiate pseudo-Cushing from Cushing Syndrome. We will include study whose patients have confirmed diagnosis of Cushing's syndrome or pseudo-Cushing and underwent the DDAVP test. The outcomes that will be analyzed are sensitivity, specificity, positive and negative predictive values, positive and negative likelihood ratios, of the aforementioned test. Our data sources will be EMBASE, PubMed and Virtual Health Library (BVS). For all identified studies, two reviewers independently will assess the titles and summaries of them, in order to find all studies that meet our eligibility criteria. The quality of the included studies will be analyzed according the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies). A meta-analysis of the results of the included studies will be performed using the Meta-DiSc program. It is expected by the end of this project to report the accuracy of DDAVP test in the differential diagnosis of Cushing's syndrome and pseudo-Cushing. Thus, this test may or not be routinely used to differentiate these two clinical cases.