Value of neutrophil/lymphocyte ratio, N-terminal pro-B-type natriuretic peptide, urea, and creatinine for the prediction of acute kidney injury in acute heart failure: a retrospective observational study

Abstract Objective: Early identification of acute kidney injury (AKI) is essential to improve the prognosis of patients with acute heart failure (AHF). We aimed to determine the utility of neutrophil/lymphocyte ratio (NLR), N-terminal prohormone of brain natriuretic peptide (NT-proBNP), urea, and creatinine (Cr), as well as combinations of these, for the prediction of AKI in patients with AHF. Methods: A total of 153 patients with AHF under the care of Sun Yat-sen Memorial Hospital, Sun Yat-sen University from October 2009 to October 2019 were included in this retrospective observational study. Their NLR, NT-proBNP, urea, and Cr concentrations were measured on admission. AKI was defined using the Acute Kidney Injury Network criteria. Receiver operating characteristic (ROC) curves, the areas under the curves (AUCs), sensitivity, and specificity were employed to evaluate the ability of each biomarker and their combinations to identify AKI. This study was approved by the Ethics Committee of Sun Yat-sen Memorial Hospital, Sun Yat-sen University (approval No. SYSEC-KY-KS-2021-126) on June 22, 2021. Results: Forty-six (30.1%) participants developed AKI during hospitalization. The NLR and NT-proBNP of the participants with AKI were higher than those without (NLR: median 7.886 vs 4.717, P < 0.0001; NT-proBNP, median 6774 vs 2786pg/mL, P < 0.0001). ROC analyses demonstrated that high NLR and NT-proBNP were associated with higher incidences of AKI (NLR: cut-off 5.681, AUC 0.716, sensitivity 58.9%, specificity 80.4%; NT-proBNP: cut-off 5320pg/mL, AUC 0.700, sensitivity 72.9%, specificity 65.2%). Moreover, a combination of NLR, NT-proBNP, urea, and Cr yielded an AUC of 0.815, sensitivity 80.4%, and specificity of 74.8%. In addition, the AUCs for the prediction of AKI in the participants with New York Heart Association (NYHA) classes II, III, and IV were 0.936, 0.860, and 0.772, respectively, using this combination. Conclusion: A combination of NLR, NT-proBNP, urea, and Cr, measured at admission, may represent a promising tool for the prediction of AKI in patients with AHF. This method performs best for AKI risk assessment in patients with NYHA II, followed by those with NYHA III or IV.