Addition of platelet-lymphocyte ratio to risk factors to improve the early prediction of acute kidney injury and mortality in critically ill neonates

To determine whether early neutrophil, lymphocyte, and platelet ratio (NLPR), neutrophil-lymphocyte ratio (NLR), and platelet-lymphocyte ratio (PLR), calculated based on easily available parameters in complete blood count, are associated with the development of acute kidney injury (AKI) and mortality during neonatal intensive care unit (NICU) stay, and to evaluate whether these ratios could act as a predictor of AKI and mortality in neonates.The pooled data of 442 critically ill neonates from our previously published prospective observational studies of urinary biomarkers were analyzed. Complete blood count (CBC) was measured on NICU admission. The clinical outcomes included AKI developed during the first 7 days after admission and NICU mortality.Of the neonates, 49 developed AKI and 35 died. The association of the PLR, but not NLPR and NLR, with AKI and mortality remained significant after adjustment for potential confounders including birth weight and illness severity as assessed by the score for neonatal acute physiology (SNAP). The area under the curve (AUC) of the PLR for predicting AKI and mortality was 0.62 (P=0.008) and 0.63 (P=0.010), respectively, with additional predictive value when combined with other perinatal risk factors. The combination of PLR with birth weight, SNAP, and serum creatinine (SCr) had an AUC of 0.78 (P<0.001) in predicting AKI, and its combination with birth weight and SNAP had an AUC of 0.79 (P<0.001) in predicting mortality.Low PLR on admission is associated with increased risk for AKI and NICU mortality. Although the PLR alone is not predictive of AKI and mortally, it adds predictive value to other risk factors for AKI prediction in critically ill neonates.