Background and aim: Minimal hepatic encephalopathy (MHE) is characterized by time of reaction, executive function, as well as high disability and mortality. There is an absence of a Gold Standard for its prognosis; the application of psychometric tests combined with neurophysiological tests to identify the presence of MHE is worldwide accepted. Critical flicker frequency (CFF)test is commonly used; however, there exist discrepancies with respect to the determination of the cutoff value.
Material and methods: While analyzing CFF's continuous scale, the application of Logistic Regression Analysis proved to be suitable to define the appropriate cutoff point. A set of 59 patients with hepatic cirrhosis were studied. The ROC curve showed ambiguities in the determination of the cutoff point when using “Youden's index” as well as the closest point on the graph to the upper left corner point. It was decided to apply Regression Analysis, Algebra, Analytic Geometry and Differential Calculus to determine the cutoff point. MINITAB software was used for computations.
Results: Regression allowed two different ways to reach the same conclusion: CFF's cutoff point is 38.0Hz to identify patients with MHE. CFF test is a promising tool but to be of help, it needs a valid cutoff point in the scale.
Financing: Project supported by the SS / IMSS / ISSSTE-CONACYT Sector Research Fund on Health and Social Security. 1-2017. 289979.
Project supported by the Budgetary Program E015 Research and Technological Development in Health of the ISSSTE.
Conflicts of interest: The authors have no conflicts of interest to declare.
