Predictive value of combined detection of blood Urea nitrogen and Neutrophil-to-lymphocyte ratio for identifying severe pneumonia complicated with sepsis in neonates

Newborns with severe pneumonia are at a high risk of developing sepsis, and early identification of this risk can improve the prognosis for the affected children. The purpose of this study was to evaluate the predictive value of combining blood urea nitrogen (BUN) and neutrophil-to-lymphocyte ratio (NLR) in diagnosing neonatal severe pneumonia complicated with sepsis (NSPCS). We retrospectively included 194 newborns hospitalized from January 2018 to December 2021. Of these, 51 newborns with severe pneumonia developed sepsis. Clinical and laboratory data were collected from electronic medical records. The newborns were divided into severe pneumonia and sepsis groups. Multivariate logistic regression analysis was performed to determine whether BUN and NLR were independent predictors of NSPCS. The predictive value of combining BUN and NLR was assessed using receiver operating characteristic (ROC) curve analysis. Newborns with severe pneumonia complicated by sepsis had elevated levels of BUN (P < 0.001) and NLR (P = 0.003). Correlation analysis indicated a positive correlation between NSPCS and levels of BUN (r = 0.341, P < 0.001) and NLR (r = 0.213, p = 0.003). Multiple logistic regression analysis revealed that BUN and NLR were independent risk factors for NSPCS. ROC curve analysis revealed that combining BUN and NLR had better efficacy in identifying NSPCS (AUC = 0.757, 95% CI: 0.681–0.834, P < 0.001), with significantly better discriminatory ability than either BUN (AUC = 0.724, 95% CI: 0.643–0.804, P < 0.001) or NLR (AUC = 0.640, 95% CI: 0.545–0.735, P = 0.003) alone. The combined detection of BUN and NLR was a valuable biomarker for identifying NSPCS. Newborns with severe pneumonia are at a high risk of developing sepsis, and early identification of this risk can improve the prognosis for the affected children. The clinical symptoms of neonatal sepsis are nonspecific, and the diagnostic criteria are unclear. Identifying effective biomarkers for early detection of neonatal severe pneumonia complicated with sepsis (NSPCS) could significantly improve clinical outcomes. This study determined the risk factors for NSPCS. The combined measurement of BUN and NLR levels may be a valuable biomarker for identifying NSPCS, providing clinicians with a reference for accurate diagnosis and treatment.