Abstract Disclosure: V.M. Soriano: None. C. Espinel Pachon: None. Diagnosis performance of insulin surrogate indices for predicting insulin resistance in young men defining as reference the Matsuda index – An exploratory case-control study conducted in Latin America population Víctor Antonio Malagón – Soriano1, Álvaro Javier Burgos – Cárdenas1, Maria Fernanda Garcés2, Cristian Felipe Espinel – Pachon1, Roberto Franco – Vega3, Jorge Andres Rubio – Romero4, Sofia Alexandra Caminos – Cepeda5, Ezequiel Lacunza6, Ariel Iván Ruiz – Parra4, Jorge Eduardo Caminos2 1Department of Internal Medicine, 2Department of Physiology, 3Endocrinology Unit - Department of Internal Medicine, 4Department of Obstetrics & Gynecology, School of Medicine Universidad Nacional de Colombia, Bogotá 11001, Colombia. 5School of Medicine, Universidad Pompeu Fabra; Barcelona 08002, Spain.6Centro de Investigaciones Inmunológicas Básicas y Aplicadas (CINIBA), Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata 1900, Argentina. Correspondence: Jorge Eduardo Caminos, MSc. PhD., Department of Physiology, School of Medicine, Universidad Nacional de Colombia, Carrera 30 No. 45-03, Edificio 471 Oficina 406, Bogotá, Colombia, E-mail: jecaminosp@unal.edu.coRunning title: Diagnosis performance of Insulin Surrogate Indices using as reference the Matsuda index. Key words: Insulin surrogate indices, diagnosis performance, Matsuda index, healthy and insulin resistant young men Abstract Insulin plays an essential role in glucose and lipid homeostasis. Changes in insulin sensitivity in adipose tissue, liver and muscle occur in the course of different metabolic disorders, and have been proposed to be a potential contributor to obesity and type 2 diabetes. The euglycemic-hyperinsulinemic clamp technique is the gold standard approach for assessing insulin sensitivity in humans, with the disadvantages of being expensive, labor intensive, and time consuming. Therefore, this study aimed to investigate the diagnosis performance of insulin surrogate indices using as reference the Matsuda index, in healthy and insulin resistant young men in Latin America population. Thus, the current cross-sectional study was conducted in healthy (n=48) and insulin resistant (n=45) young adult men (18–31 year old) using the Matsuda index cut-off value as reference to determine insulin sensitivity/resistance. Receivers operating characteristic curves (ROC) were used to determine the cut-off, sensitivity, and specificity values for QUICKI, HOMA-IR, TG/HDL-C, TyG, TyG-WC, TyG-BMI, LAP and VAI. TyG-WC (AUC=1.0) and TyG-BMI (AUC=1.0) indices showed the highest diagnostic performance with high sensitivity and specificity to predict insulin resistance in young men. In addition, TyG-BMI index showed a statistically significant stronger correlation with waist circumference (WC), when compared with HOMA-IR, Matsuda and QUICKY indices. In conclusion, we were able to diagnose insulin resistance with high sensitivity and specificity in young individuals -supposedly metabolically healthy- who do not meet the criteria for metabolic syndrome diagnosis, using widely available, low-cost, and reliable surrogate indices. Additionally, the TyG-WC and TyG-BMI indices were the better predictors of insulin resistance. The cut-off values used to define insulin resistance in our Latin America population studied were similar to recent studies in the United States population, despite clinical and racial/ethnic differences. Presentation: Thursday, June 15, 2023