The Relationship Between the Triglyceride-Glucose Index, and HbA1c and Insulin Resistance in Prediabetic Patients

INTRODUCTION: The triglyceride-glucose index (TyGi) is recommended as a reliable and simple insulin resistance (IR) marker in patients. This study aimed to clarify the role of TyGi in prediabetic patients and to compare its correlation with insulin resistance.
METHODS: A total of 176 patients who applied to the Endocrinology Department outpatient clinic and underwent a 3-hour OGTT were included in the study. The patients were divided into two groups (normal, prediabetes) according to the OGTT results. IR was calculated using the homeostatic model assessment (HOMA-IR) formula. The ADA criteria were used to diagnose prediabetes. The formula ln (fasting triglyceride [mg/dL]×fasting glucose [mg/dL]/2) was used to determine the TyGi.
RESULTS: Higher mean TyGi (8.79±0.08 vs. 8.43±0.05) and HOMA-IR (4.28±0.43 vs. 2.41±0.21) values were observed in prediabetic subjects compared to normoglycemic subjects. During the OGTT, TyGi correlated with glucose, HbA1c, and HOMA-IR measurements. The area under the curve (AUC) for HbA1c (0.754) was greater than that for HOMA-IR (0.725) and TyGi (0.674) in diagnosing prediabetes. The cut-off values for prediabetes were TyGi > 8.50 (sensitivity: 66.1%, specificity: 42.7%) and HOMA-IR > 2.25 (sensitivity: 62.5%, specificity: 32.6%).
DISCUSSION AND CONCLUSION: TyGi is nearly as effective as HbA1c as a diagnostic marker for prediabetes, and the cut-off points for identifying prediabetes were determined as TyGi > 8.50 and HOMA-IR > 2.25.