Association Between the Triglyceride–Glucose Index and Carotid Atherosclerosis Subtypes in Type 2 Diabetes Mellitus: Insights From a Cross‐Sectional Study

Background Studies have indicated that the triglyceride–glucose (TyG) index is associated with carotid atherosclerosis, but results have been inconsistent across populations. However, evidence regarding its relationship with specific subtypes of carotid atherosclerosis—carotid intima–media thickening (cIMT), plaque, and stenosis—in patients with Type 2 diabetes mellitus (T2DM) remains limited. This study aimed to investigate the subtype‐specific associations between the TyG index and carotid atherosclerosis in T2DM patients. Methods A total of 7200 patients with T2DM were enrolled in this cross‐sectional study. The TyG index was calculated as ln fasting triglyceride (mg/dL) × fasting glucose (mg/dL)/2. Multivariable logistic regression models were used to evaluate the associations between the TyG index and carotid atherosclerosis subtypes (cIMT thickening, plaque, and stenosis). Restricted cubic spline (RCS) regression was applied to explore potential nonlinear relationships. Subgroup analyses were conducted according to sex, age, body mass index (BMI), smoking status, and hypertension. Results As a continuous variable, the TyG index was positively associated with cIMT thickening (OR = 1.68, 95% CI: 1.29–2.19) and carotid stenosis (OR = 1.26, 95% CI: 1.021–1.66) but was negatively associated with carotid plaque (OR = 0.89, 95% CI: 0.80–0.99). Compared with the lowest quartile (Q1), the highest quartile (Q4) of the TyG index was significantly associated with cIMT (OR = 2.48 and 95% CI: 1.35–4.65) and stenosis (OR = 2.13 and 95% CI: 1.41–3.72). Subgroup analyses showed stronger associations between the TyG index and cIMT in women (OR = 4.00 and 95% CI: 1.20–15.40), younger individuals (OR = 3.15 and 95% CI: 1.23–9.13), those with normal BMI (OR = 7.03 and 95% CI: 1.94–30.44), and those without hypertension (OR = 2.09 and 95% CI: 1.00–4.71). The RCS regression model suggested a nonlinear correlation between the TyG index and cIMT. Conclusions The TyG index is differentially associated with carotid atherosclerosis subtypes in patients with T2DM, showing a stronger relationship with early vascular changes (cIMT) than with advanced lesions. These findings suggest that the TyG index may serve as a simple and useful marker for early vascular risk assessment and risk stratification in T2DM.