Aim. Тo assess the association and discriminatory performance of the low-density lipoprotein cholesterol to high-density lipoprotein cholesterol (LDL-C/HDL-C) ratio and non-HDL-C in relation to coronary artery disease (CAD) severity in patients with chronic coronary syndrome (CCS).

Material and methods. This multicenter, cross-sectional study included 500 adult patients diagnosed with CCS who underwent coronary angiography. Patients were stratified into two groups according to SYNTAX score: a high SYNTAX score group (≥33; n=149) and a low-to-intermediate group (<33; n=351). Fasting lipid profiles were measured prior to angiography. The LDL-C/HDL-C ratio and non-HDL-C levels were calculated and analyzed. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the ability of these markers to discriminate severe CAD. Optimal cutoff values, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were determined.

Results. The LDL-C/HDL-C ratio demonstrated higher discriminatory ability within the study population than non-HDL-C for identifying patients with high SYNTAX scores, with AUC values of 0.745 (95% CI: 0.689-0.802) and 0.703 (95% CI: 0.649-0.757), respectively, both markers demonstrated discriminatory ability for identifying patients with high SYNTAX scores. An LDL-C/HDL-C cutoff value >2.3 yielded a sensitivity of 58.39% and specificity of 96.58%, with PPV of 87.9% and NPV of 84.5%. For non-HDL-C, a cutoff value >2.48 mmol/L provided 73.15% sensitivity and specificity, with PPV of 45.6% and NPV of 84.7%.

Conclusion. Both the LDL-C/HDL-C ratio and non-HDL-C are significantly associated with the severity of coronary artery disease in patients with CCS. The LDL-C/HDL-C ratio demonstrated favorable discriminatory ability and may serve as a useful adjunctive marker for the assessment of CAD severity in patients with CCS.