Supplementary Material for: Comparison between triglyceride glucose index and homoeostasis model assessment of insulin resistance in their associations with vascular dysfunction: Danyang Study

Introduction: While Insulin resistance (IR) is an established risk factor for cardiovascular disease, vascular dysfunction represents a critical early pathological link. Although prior studies support the association between IR and vascular dysfunction, it remains unknown whether IR assessed by homeostasis model assessment of insulin resistance (HOMA-IR) or the triglyceride-glucose index (TyG index) is more closely related to specific markers of vascular dysfunction.
Methods: 2278 participants (59.3% women; average age, 56.7±11.0 years) were recruited in this study. The HOMA-IR and TyG index was calculated using [fasting insulin (μIU/mL)×fasting glucose (mmol/L)/22.5] and ln[fasting triglyceride (mg/dL)×fasting glucose (mg/dL)/2], respectively. Vascular measurements included brachial-ankle pulse wave velocity (baPWV), cardio-ankle vascular index (CAVI), and urinary albumin-to-creatinine ratio (UACR), representing macro- and micro-vascular dysfunction, respectively.
Results: Irrespective of the assessment methods of IR, both the TyG index and HOMA-IR were all significantly associated with the vascular indices before (P < 0.001) and after full adjustment (P ≤ 0.041). The standardized regression coefficients of the vascular dysfunction with the TyG index were comparable to those with the HOMA-IR after adjustment for various confounders (0.07 15.8 versus 0.05 18.2; Pcompare ≥ 0.108). In multivariable logistic regression analysis, the TyG index was significantly associated with higher risk of arterial stiffness (odds ratio [OR] = 1.37 and 1.26 for abnormal baPWV and CAVI, respectively; P ≤ 0.035), while the HOMA-IR was tightly associated with higher risk of abnormal CAVI (OR = 1.54; P < 0.001) and albuminuria (OR = 1.40; P = 0.006). Further subgroup analyses showed that a more significant association between the TyG index and the prevalence of increased arterial stiffness was observed in women and non-diabetic participants, and participants without chronic kidney disease (CKD) (P ≤ 0.025), while a more significant association between the HOMA-IR and the prevalence of abnormal CAVI and albuminuria was detected in younger individuals, females, normotensive or normoglycemic subjects. (P ≤ 0.035).
Conclusion: The TyG index demonstrated a stronger association with arterial stiffness (baPWV) than HOMA-IR, whereas the HOMA-IR showed a more pronounced association with albuminuria, with both correlations being significant in women.