Association between apolipoproteins and coronary artery disease (CAD), a case–control observational study
Background: - Coronary artery disease (CAD) is a leading cause of morbidity and mortality worldwide. Although conventional lipid parameters are routinely used for cardiovascular risk assessment, they may not fully represent the true atherogenic burden. Apolipoproteins, the structural protein components of lipoproteins, have emerged as stronger predictors of CAD risk. Among them, Apolipoprotein B (ApoB) reflects the total number of atherogenic particles, while Apolipoprotein A-I (ApoA-I) represents anti-atherogenic HDL particles. The ApoB/ApoA-I ratio integrates these opposing effects and may serve as a superior marker of atherogenic risk. Aim: To assess the association of Apolipoprotein B, Apolipoprotein A-I, and their ratio with coronary artery disease and its severity, and to compare their predictive value with conventional lipid parameters. Materials and Methods: This case–control study included 100 participants—50 angiographically confirmed CAD patients and 50 age- and sex-matched healthy controls. Fasting blood samples were analyzed for lipid profile and serum apolipoproteins (ApoB and ApoA-I) using immunoturbidimetric methods. The ApoB/ApoA-I ratio was calculated, and CAD severity was graded based on the number of diseased coronary vessels. Statistical analysis was performed using SPSS version 25. Continuous variables were compared using Student’s t-test, and correlation analyses were performed using Pearson’s coefficient. Results: CAD patients had significantly higher total cholesterol (212.4 ± 35.7 vs 176.8 ± 28.9 mg/dL, p < 0.001), triglycerides (176.2 ± 42.6 vs 138.4 ± 30.7 mg/dL, p < 0.001), LDL-C (134.8 ± 28.9 vs 105.3 ± 24.6 mg/dL, p < 0.001), and ApoB (130.7 ± 24.8 vs 96.5 ± 18.1 mg/dL, p < 0.001). Conversely, HDL-C (37.6 ± 7.8 vs 48.2 ± 8.5 mg/dL, p < 0.001) and ApoA-I (110.5 ± 18.6 vs 142.8 ± 20.2 mg/dL, p < 0.001) were significantly lower in CAD patients. The ApoB/ApoA-I ratio was markedly elevated in CAD patients (1.21 ± 0.28 vs 0.68 ± 0.19, p < 0.001) and increased proportionally with disease severity (SVD: 1.05 ± 0.20, DVD: 1.20 ± 0.22, TVD: 1.39 ± 0.25; p < 0.001). ApoB correlated positively with LDL-C (r = 0.69, p < 0.001), while ApoA-I showed a positive correlation with HDL-C (r = 0.71, p < 0.001).