GDF15 and acute kidney injury: The aim of our study was to employ biomarkers in association with acute kidney injury, including neutrophil gelatinase-associated lipocalin (NGAL), calprotectin, kidney injury molecule-1 (KIM-1), cystatin C, and growth differentiation factor 15 (GDF-15), along with SOFA and APACHE scores in predicting ventilator dependence in critically ill surgical patients.