Systemic inflammatory index as a predictive marker for the severity of coronary artery disease in individuals with chronic kidney disease.

Objective: To evaluate the correlation between the inflammatory intensity, as indicated by the systemic inflammatory index (SII), and the severity of coronary artery disease (CAD) in patients with chronic kidney disease (CKD).

Methods: A total of 280 CKD patients who underwent coronary angiography were enrolled. CAD was evaluated using the Gensini score (GS). Patients were divided into the low, medium and high SII groups according to the tertiles of the SII values. Logistic regression analysis was conducted to analyze the relationship between SII and GS. The cutoff points for the sensitivity and specificity of SII in predicting GS were estimated by performing the receiver operating characteristic curve analysis.

Results: Patients in the higher SII group had a higher prevalence of CAD (P = 0.013). In addition, the high SII group had more patients with complex CAD (triple-vessel disease and/or left main coronary artery stenosis) and chronic total occlusion lesions, and more patients required revascularization (P < 0.05). Correlation analysis suggested a positive relationship between SII and GS, and in comparison to neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio, SII displayed a stronger correlation with GS (r = 0.332, P < 0.001). Multifactorial logistic regression analysis revealed that SII is independently associated with the severity of CAD (adjusted OR = 1.14, 95% CI: 1.08-1.21, P < 0.01), particularly among elderly patients (age ≥ 65 years). Receiver operating characteristic curve analysis indicated that the optimal cutoff value for SII in predicting severe coronary artery stenosis (GS > 60) was 6.01 (sensitivity: 76.30%, specificity: 53.50%), with an area under the curve (AUC) of 0.705 (95% CI: 0.642-0.768, P < 0.001), which was statistically significantly better than platelet-to-lymphocyte ratio (AUC = 0.646, 95% CI: 0.579-0.713, P < 0.001) and neutrophil-to-lymphocyte ratio (AUC = 0.643, 95% CI: 0.574-0.712, P < 0.001).

Conclusions: In patients with CKD, SII is independently associated with the severity of CAD, especially in individuals aged 65 years or older. Furthermore, SII functions as a predictive marker for the severity of coronary lesions.