Background: This study aims to investigate the correlation between the low-density lipoprotein cholesterol (LDL-C)/high-density lipoprotein cholesterol (HDL-C) ratio, in combination with complete blood count and coagulation panel parameters, and both the severity of coronary artery lesions and prognosis in patients with early-onset coronary heart disease, and to provide novel, comprehensive clinical indicators for risk assessment and prognosis evaluation in this patient population.

Methods: A retrospective study was conducted on the clinical data of 159 patients diagnosed with early-onset coronary heart disease through initial coronary angiography between January 2023 and August 2025. Patients were categorized into three groups based on coronary lesion severity: a mild lesion group (n = 78), a moderate disease group (n = 59), and a severe disease group (n = 22). Lipid profiles [total cholesterol (TC), triglycerides (TG), LDL-C, HDL-C, LDL-C/HDL-C ratio], fasting blood glucose, uric acid, and coagulation parameters [prothrombin time (PT), prothrombin time ratio (PTR), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen (FIB)], complete blood count [hemoglobin (HGB), red cell distribution width-coefficient of variation (RDW-CV), red cell distribution width-standard deviation (RDW-SD), mean platelet volume (MPV), platelet distribution width (PDW)] were detected, and the correlation between statistically significant indicators and the severity of coronary artery lesions was analyzed. Participants were divided into the MACE group and the non-MACE group based on the occurrence of major adverse cardiac events (MACE) within 100 days, and binary logistic regression analysis was applied to identify MACE risk factors.

Results: The severe group showed higher TC, LDL-C, LDL-C/HDL-C, fasting blood glucose, and uric acid levels than the moderate group, which in turn had higher levels than the mild group; TG was higher than in the moderate/mild groups; HDL-C was lower than in the moderate group but higher than in the mild group (p < 0.05). The severe group had higher PT, PTR, APTT, TT, and FIB than the moderate group, which in turn was higher than the mild group (p < 0.05). There were no statistically significant differences in HGB levels among the groups (p > 0.05); however, the severe group had higher RDW-CV, RDW-SD, MPV, and PDW than the moderate group, and the mild group had the lowest (p < 0.05). Kendall's correlation coefficients indicated that TC, TG, LDL-C, LDL-C/HDL-C, fasting blood glucose, uric acid, PT, PTR, APTT, TT, FIB, RDW-CV, RDW-SD, MPV, and PDW were positively correlated with the severity of coronary artery lesions (τ = 0.375, 0.372, 0.346, 0.448, 0.305, 0.239, 0.388, 0.310, 0.299, 0.447, 0.364, 0.476, 0.226, 0.401, 0.466, p < 0.001), HDL-C was negatively correlated with the severity of coronary artery lesions (τ = –0.410, p < 0.001). The incidence of MACE was highest in patients with severe early-onset coronary heart disease, followed by moderate and mild severity (χ² = 23.283, p < 0.001). Binary logistic regression analysis revealed that severity of coronary artery disease (severe), LDL-C/HDL-C ratio, fasting blood glucose, uric acid, PT, APTT, TT, FIB, RDW-SD, and PDW were all independent predictors of MACE in patients with early-onset coronary heart disease (p < 0.05).

Conclusion: In patients with early-onset coronary heart disease, LDL-C/HDL-C ratio, coagulation function indicators (PT, APTT, TT, FIB), and blood routine parameters (RDW-SD, PDW) show significant positive correlations with the anatomical severity of coronary artery lesions and are closely associated with increased short-term adverse prognosis risk.