Modified Triglyceride-Glucose Indices for Mortality Prediction in Cardiovascular Disease Patients with diabetes or pre-diabetes: Analysis of NHANES 1999-2018

Background The triglyceride-glucose (TyG) index is an emerging indicator for cardiovascular disease risk assessment. However, the predictive value of modified TyG indices in patients with cardiovascular disease (CVD) and comorbid diabetes or prediabetes remains unclear. Objective To evaluate the efficacy of modified TyG indices (TyG-BMI, TyG-WHtR, and TyG-WC) in predicting all-cause and cardiovascular mortality among CVD patients with diabetes or prediabetes. Methods Using data from the National Health and Nutrition Examination Survey (NHANES) 1999–2018, we included 1,903 adult patients with CVD and comorbid diabetes or prediabetes. Cox proportional hazards models were used to assess the relationship between TyG-related indices and mortality. Results After full adjustment for confounding factors, the original TyG index showed a significant positive association with all-cause mortality (HR for highest vs. lowest quartile: 1.85; 95% CI: 1.38–2.49, p < 0.01). Modified TyG indices demonstrated non-linear relationships with mortality, exhibiting threshold effects. Subgroup analyses revealed that TyG-BMI had stronger predictive power in populations < 60 years old, while TyG-WHtR performed better in females. Conclusion The original TyG index is an effective predictor of mortality in CVD patients with diabetes or prediabetes. Modified TyG indices show complex non-linear relationships, requiring further validation for clinical application. These findings provide new perspectives for individualized cardiovascular risk assessment.