Serum Interleukin-18, Kidney Injury Molecule-1, and the Renal Resistive Index for Predicating Acute Kidney Injury in Critically Ill Patients with Sepsis

Interleukin-18 (IL-18) is a pro-inflammatory cytokine that rises approximately 24–48 h before a diagnosis of acute kidney injury (AKI). Kidney injury molecule-1 (KIM-1) is one of the most promising early biomarkers. It participates in the process of both kidney injury and healing, although the precise mechanism of the restoration of tubular integrity after injury still remains unclear. The renal resistive index (RRI) is used for evaluating changes in intrarenal perfusion occurring in renal parenchyma diseases. The study included 80 critically ill patients with sepsis, divided into 40 patients who developed AKI and 40 patients without AKI. All patients were evaluated through their history, clinical examination, laboratory investigations of serum IL-18 and KIM-1, and the RRI. Serum IL 18, serum KIM-1, and the RRI were significantly higher in critically ill patients with sepsis and AKI. Receiver operating characteristic analysis for detecting AKI 1 day after admission showed that the area under the curve (AUC) for serum IL-18 was 86.1%, the AUC for serum KIM-1 was 86%, and the AUC for the RRI was 88%, demonstrating statistical significance for the diagnosis of AKI within the next 24 h. Serum IL-18, KIM-1, and the RRI represent early predictors of AKI in critically ill septic patients.