The predictive value of D-dimer and neutrophil-to-lymphocyte ratio for the severity of severe pneumonia in children

Severe pneumonia is typically characterized by severe pulmonary inflammatory responses. This study evaluated the predictive value of D-dimer (DD) and neutrophil-to-lymphocyte ratio (NLR) for disease severity in children with severe pneumonia. Children with severe pneumonia (280 cases) were enrolled and divided into the critical and non-critical groups based on the pediatric critical illness score (PCIS). Clinical data were collected at patients’ initial admission. Correlations of DD and NLR with the PCIS, their predictive value and the independent predictors for disease severity in children with severe pneumonia were assessed by Spearman test, receiver operating characteristic curve and multivariate logistic regression. Outcomes were determined as per the 28-day disease progression. The critical group showed higher DD and NLR than the non-critical group. DD and NLR negatively correlated with the PCIS. Children in the higher DD quartile group showed higher systolic blood pressure (SBP), NLR and procalcitonin, and lower platelet and PCIS. Children in the higher NLR quartile group had higher SBP, DD and procalcitonin, and platelet and lower PCIS. Areas under the curve to predict severe pneumonia severity were 0.805, 0.883 and 0.918 for DD, NLR and their combination, suggesting superior diagnostic value of their combination for disease severity. The critical group (59.05%) had higher 28-day poor outcomes of pneumonia than the non-critical group (18.29%). DD and NLR were independent risk factors for the disease severity in severe pneumonia children. Elevated DD and NLR have certain predictive value for disease severity and poor prognosis in severe pneumonia children.