The Systemic Immune-Inflammation Index and High-Sensitivity C-Reactive Protein to High-Density Lipoprotein Cholesterol Ratio Predict Moderate and Severe Coronary Artery Stenosis in Older Patients with Coronary Heart Disease

Objective: Coronary heart disease (CHD) stems from functional and organic coronary artery stenosis (CAS). This study explored associations of the systemic immune-inflammation index (SII) and high-sensitivity C-reactive protein to high-density lipoprotein cholesterol ratio (hsCRP/HDL-C) with CAS severity in older patients with CHD. Methods: This retrospective analysis recruited 786 older patients with CHD, with their clinical data and laboratory parameters collected. Patients were allocated into training and validation sets (7:3, randomization) or into mild, moderate, and severe stenosis groups according to Gensini scores (GS). Correlations of SII and hsCRP/HDL-C with GS, influencing factors for moderate-to-severe CAS, and their diagnostic value in older patients with CHD or complicated with hypertension and/or diabetes were assessed using Spearman’s, univariate/multivariate logistic regression, and receiver operating characteristic curve analyses, respectively. Results: Elevated SII and hsCRP/HDL-C were observed in patients with moderate-to-severe stenosis, which demonstrated certain correlations with GS, and were independent risk factors (IRFs) for moderate-to-severe CAS in older patients with CHD in both sets. The comparable regression coefficients between the two sets suggested good model consistency and no significant multicollinearity. The area under the curve of the combination of SII and hsCRP/HDL-C for predicting CAS severity was outperforming either marker alone. Hypertension significantly affected the discriminating performance of SII. SII remained stable in the hypertensive population, but its efficacy decreased evidently in the non-hypertensive population. Conclusion: SII and hsCRP/HDL-C are IRFs for moderate-to-severe CAS in older patients with CHD, and their combination yields good predictive performance. Regression coefficients were well consistent between the two datasets. A study of 786 elderly CAD patients from January 2023 to June 2025 excluded those with incomplete records, severe dysfunctions, complications, autoimmune diseases, recent cerebrovascular disease and previous interventions. Patients were split into training (N=550) and validation (N=236) groups at a 7:3 ratio. Based on Gensini scores, they were categorized into mild (≤ 20 score, N=214/85), moderate (21-45 score, N=196/82) and severe stenosis (> 45 score, N=140/69). Data collected included demographics, medical history and lab results. Analyses involved baseline comparisons, Spearman correlation, logistic regression and ROC curve analysis. SII and hsCRP/HDL-C values emerged as key predictors of coronary artery stenosis in elderly CAD patients.Flowchart on elderly CAD patient study: classification, data collection and analysis methods. Keywords: elderly coronary heart disease, coronary artery stenosis, systemic immune-inflammation index, high-sensitivity c-reactive protein to high-density lipoprotein cholesterol ratio, correlation