Atherogenic lipid indices and carotid atherosclerotic burden: Comparative performance of AIP, TG/HDL-C, non-HDL-C, LDL/HDL-C and remnant cholesterol

Background and objectives: Composite atherogenic lipid indices may reflect residual vascular risk beyond conventional lipid measurements, but their comparative relationships with carotid structural disease remain uncertain. This study compared the atherogenic index of plasma (AIP), triglyceride/high-density lipoprotein cholesterol (TG/HDL-C), non-HDL-C, LDL/HDL-C and remnant cholesterol against conventional lipids for associations with carotid intima-media thickness (cIMT) and plaque. Material and methods: This analytical cross-sectional study included 447 patients undergoing carotid Doppler assessment at Jagannath Gupta Institute of Medical Sciences & Hospital, Kolkata. As this is retrospective study, it does not require any ethical permission from local ethical committee. Derived indices were calculated from routine lipid measurements. Age- and sex-adjusted correlations, separate multivariable linear and logistic regression models, standardized effect estimates, model-fit comparisons and receiver-operating-characteristic analyses were performed. Models adjusted for age, sex, hypertension, HbA1c, smoking and estimated glomerular filtration rate; bootstrap intervals and paired DeLong tests assessed plaque discrimination. Results: Mean age was 65.5 ± 12.9 years; 71.4% had hypertension and 42.8% had diabetes. Mean cIMT was 1.108 ± 0.227 mm, and plaque was identified in 209 of 377 patients (55.4%) with interpretable coding. None of the five composite indices independently correlated with cIMT or overall, bilateral or internal carotid plaque. Total cholesterol (standardized β=0.100; P=0.033) and HDL-C (β=0.130; P=0.006) were positively associated with mean cIMT. Plaque prediction scarcely changed when non-HDL-C or AIP was added to the clinical model (AUROC 0.663, 0.665 and 0.664, respectively); neither increment was significant. Conclusion: Single-measurement composite lipid indices did not outperform conventional lipids for cross-sectional carotid phenotyping in this older, high-risk cohort. Prospective evaluation of cumulative lipid exposure and plaque characteristics is warranted. before recommendations for routine clinical adoption.