The Triglyceride/High-Density Lipoprotein Cholesterol Ratio, the Small Dense Low-Density Lipoprotein Phenotype, and Ischemic Heart Disease Risk

This study investigated the relevance of using the plasma triglyceride to high-density lipoprotein cholesterol ratio (Log TG/HDL-C) for the prediction of the small dense lowdensity lipoprotein (LDL) phenotype and the risk of ischemic heart disease (IHD). Analyses were based on data from the Quebec Cardiovascular Study in a cohort of 2072 men free of IHD at baseline, among whom 262 had a first IHD event (coronary death, non fatal myocardial infarction and unstable angina) during a 13-year follow-up period. LDL particle size phenotype was characterized using 2–16% polyacrylamide gradient gel electrophoresis (PAGGE) of whole plasma. There were significant associations between the Log TG/HDL-C ratio and features of LDL size phenotype such as the proportion of LDL with a diameter <255Å (r = 0.43, p < 0.001) and LDL peak particle size (r = -20.55, p < 0.001). However, the Log TG/HDL-C ratio brought no additional value (p ≥ 0.1) in predicting the small dense LDL phenotype (area under the receiver operating curve (AUROC = 71.9%) compared to TG alone (AUROC = 71.2%) or to a combination of Log TG and HDL-C (AUROC = 72.4%) after multivariate adjustment for non lipid risk factors. Finally, elevations in the Log TG/HDL-C ratio did not improve the discrimination of incident IHD cases from non IHD cases compared to the use of plasma TG levels alone (p = 0.5) or a combination of the individual TG and HDL-C values (p = 0.5). The Log TG/HDL-C ratio does not improve our ability to identify individuals with the small dense LDL phenotype compared to plasma TG levels alone. The Log TG/HDLC is also not superior to plasma TG levels alone in predicting IHD risk in men of the Québec Cardiovascular Study.