A COMPOSITE SEPSIS INFLAMMATORY INDEX (SII) COMBINING NLR, PLR, AND CRP IN NEONATAL SEPSIS: UTILITY IN PREDICTING DISEASE SEVERITY

Abstract

Background: Neonatal sepsis diagnosis and severity assessment remain challenging. Inflammatory markers such as NLR, PLR, and CRP have individually shown promise, but their combined predictive value remains underexplored.

Objective: To develop a Composite Sepsis Inflammatory Index (SII) using NLR, PLR, and CRP, and to evaluate its utility in predicting severe outcomes in neonatal sepsis.

Methods: A retrospective analysis was conducted on 147 neonates with suspected sepsis from a prospective NICU cohort. A composite score, SII = (NLR × CRP) + (PLR / 10), was derived. Diagnostic accuracy for mortality, ventilation requirement, and NICU stay >10 days was assessed using ROC analysis and logistic regression.

Results: Higher SII values were significantly associated with mortality (p<0.001), ventilation (p=0.002), and prolonged NICU stay (p=0.014). The SII demonstrated an AUC of 0.841 for predicting mortality, outperforming individual markers. Optimal cutoff of 19.8 yielded 81.2% sensitivity and 72.5% specificity.

Conclusion: The Composite Sepsis Inflammatory Index enhances predictive accuracy for severe neonatal sepsis outcomes. This simple, cost-effective tool may support early risk stratification in resource-limited NICUs.