Introduction: A high vesicoureteral reflux (VUR) grade is among the specific risk factors for febrile urinary tract infection (febrile UTI) and renal scarring. The aim of this study was to examine the predictive value of some potential hematological parameters for high-grade VUR and renal scarring in children 2 to 24 months old with febrile UTI.
Methods: We retrospectively examined the clinical features, laboratory tests, and imaging studies of 163 children 2 to 24 months old with a diagnosis of febrile UTI. The hematological parameters based on the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and white blood cell count (WBC) were calculated using a receiver operating characteristic (ROC) analysis to select which one is suitable.
Results: Of the 163 children with febrile UTI, 57 patients (35%) exhibited high-grade VUR. Regarding the predictive power for high-grade VUR, the median area under the curve (AUC) was 0.692 for NLR (sensitivity 61.4%, specificity 69.8%, P < 0.001) and 0.681 for PLR (sensitivity 63.2%, specificity 62.3%, P < 0.001). White blood cell count demonstrated the highest area under the ROC curve for diagnosis of high-grade VUR (0.884, 95% confidence interval 0.834-0.934) and an optimal cutoff value of 13.5 (sensitivity 80.7%, specificity 80.2%, P < 0.001). White blood cell count, with the highest AUC of 0.892 while the sensitivity and specificity were 83.3% and 82.8, was the preferred diagnostic index for renal scarring screening.
Conclusions: White blood cell count, NLR, and PLR were useful biomarkers closely related to children with febrile UTI who are at risk for high-grade VUR can also act as a novel marker to accurate prediction of high-grade VUR and renal scarring. Also, NLR and PLR can serve as useful diagnostic biomarkers to distinguish high-grade VUR from low-grade VUR.
Keywords: Urinary tract infection; neutrophil-to-lymphocyte ratio; platelet-to-lymphocyte ratio; vesicoureteral reflux; voiding cystourethrography.