LDL/HDL Ratio and Coronary Heart Disease in Employees of Shiraz University of Medical Sciences

Abstract

Background: Cardiovascular diseases are the leading cause of mortality in Iran, and dyslipidemia is a major contributor to cardiometabolic risk. Objectives: This study assessed the discriminatory ability of the low-density lipoprotein/high-density lipoprotein (LDL/HDL) ratio for prevalent coronary heart disease (CHD) in participants in the Shiraz University of Medical Sciences Employee Cohort Study. Methods: This cross-sectional analysis was conducted from 2017 to 2020 among 7,100 university employees aged 20 - 70 years. Eligibility criteria included active employment and the ability to complete questionnaires; individuals unwilling to participate or those with incomplete medical records were excluded. Coronary heart disease status was determined based on physician-documented diagnoses or self-report. Demographic, anthropometric, and biochemical data, including LDL, HDL, total cholesterol, triglycerides, fasting blood glucose, blood urea nitrogen, and creatinine, were obtained from standardized medical records and laboratory reports using validated protocols. Lipid ratios, including LDL/HDL, were calculated. Multivariable logistic regression was used to estimate adjusted odds ratios while controlling for age, sex, hypertension, diabetes, and other major confounders. The discriminatory performance of lipid indices was evaluated using receiver operating characteristic (ROC) curve analysis. Analyses were performed using SPSS version 26 and Python (scikit-learn), with P < 0.05 considered statistically significant. Results: Of the 7,100 participants, 332 had prevalent CHD. Age, hypertension, and fasting blood glucose were independently associated with CHD (all P < 0.05). The LDL/HDL ratio demonstrated the highest discriminatory performance among the lipid indices (area under the curve [AUC] = 0.677; 95% CI, 0.644 - 0.710), with an optimal cutoff of 2.19 (63% sensitivity and 61% specificity). Higher LDL/HDL ratios were significantly associated with greater clustering of cardiometabolic risk factors (P < 0.001). Conclusions: The LDL/HDL ratio is a simple, readily available index derived from routine lipid profiles that reflects the clustering of cardiometabolic risk factors and is associated with prevalent CHD in this working population. These findings may help inform workplace health monitoring and cardiovascular risk assessment. Study limitations include the cross-sectional design, reliance on self-reported CHD, and the single-institution cohort, which may limit the generalizability of the findings.