Neutrophil to Lymphocyte Ratio and acute kidney injury in critically ill patients.

Background: ICU-acquired acute kidney injury (AKI) is a common complication with numerous risk factors. Inflammatory mediators play a major role in the development of AKI. Several studies suggested a link between the neutrophil to lymphocyte ratio (NLR) and the platelet to lymphocyte ratio (PLR) and the occurrence of AKI. Objectives: Study a possible relationship between NLR and PLR and AKI prognosis and see if they could predict more adverse outcomes including renal replacement therapy (RRT) and mortality.Methods: 102 ICU patients with AKI were enrolled. Both CBC (to calculate NLR and PLR) and kidney function tests were performed at days 0,3,7 to study the relationship between NLR, PLR and eGFR and their correlation with the overall course of hospital stay and recovery.Results: Regarding the ability to predict mechanical ventilation, NLR had a 96% sensitivity and 81% specificity while PLR had a 92% sensitivity and 89% specificity. Both ratios had similar sensitivity in predicting shock (98%), however NLR had lower specificity. Both NLR and PLR had similar sensitivity (96.2%) and specificity (73%,71.6% respectively) in predicting the need for dialysis during hospital stay. NLR had a 50% sensitivity and 25% specificity in prediction of mortality in comparison to 50% sensitivity and 39% specificity in PLR.Conclusion: Both ratios had sufficient efficacy to predict need for mechanical ventilation, vasopressors, or dialysis. Both ratios had average accuracy in prediction of mortality.