Clinical utility of the inflammatory burden index in differentiating neonatal pneumonia from pneumonia complicated by sepsis

Differentiating sepsis from uncomplicated pneumonia in neonates remains clinically challenging. The inflammatory burden index (IBI) is a novel composite biomarker integrating inflammatory status and immune function. This study aimed to evaluate the diagnostic utility of the IBI in differentiating neonatal pneumonia with and without concomitant sepsis. We conducted a retrospective analysis of 1,383 hospitalized neonates, stratified into a pneumonia group ( n = 935) and a pneumonia-complicated-by-sepsis group ( n = 448). Clinical and laboratory data, including C-reactive protein, neutrophil count, and lymphocyte count, were collected upon admission to calculate the IBI. To assess whether the IBI was independently associated with sepsis, we performed multivariable logistic regression analysis after adjusting for relevant clinical covariates. Finally, Receiver Operating Characteristic (ROC) curve analysis was used to determine the diagnostic performance of the index. IBI levels were significantly higher in neonates with pneumonia complicated by sepsis compared to those in the pneumonia-only group ( P < 0.001). After adjusting for potential confounders in the multivariable model, a higher IBI remained independently associated with an increased prevalence of sepsis. ROC analysis showed that IBI had good diagnostic performance (area under the curve = 0.76, 95% confidence interval: 0.73–0.79, P < 0.001). IBI may serve as a non-invasive adjunctive inflammatory marker during the initial clinical assessment of neonates with suspected sepsis.