Evaluating the Prognostic Value of the Triglyceride–Glucose Index in Different Populations: A Critical Analysis

Background/Objectives: Recent studies have highlighted the Triglyceride–Glucose Index (TYG) as a significant risk factor for mortality and co-morbidities in various populations, including those with type 2 diabetes mellitus (T2DM) and cardiovascular diseases. However, its prognostic role in obese individuals remains less clear. Methods: Utilizing data from an obese cohort of 1359 subjects and from the 1999–2004 cycles of the National Health and Nutrition Examination Survey (NHANES) with 15,267 subjects, this study investigates the prognostic value of TYG and blood glucose in relation to age and sex and other factors such as metabolic syndrome, Charlson Comorbidity Index, T2DM and glucose tolerance, in predicting mortality among obese subjects. Over a median follow-up of about 13 years, 11.3% of the obese cohort and 20.6% of the NHANES cohort died. Our findings indicate that while TYG and blood glucose are significantly related to mortality, they offer only modest improvements over models incorporating age, sex, and other risk factors that showed a prognostic power of 76.1% and 86.0% in the respective cohorts. Conclusions: These results suggest that while TYG holds potential as a prognostic biomarker, its utility beyond established risk factors requires further validation in clinical settings.