Poor nutritional status and frailty associated with acute kidney injury after cardiac surgery: A retrospective observational study

Background Acute kidney injury (AKI) is a major determinant of short- and long-term morbidity and mortality following cardiac surgery. The present study examines the effect of preoperative nutritional status and frailty on this significant adverse event. Methods The data of 455 patients who underwent on-pump coronary artery bypass grafting (CABG) were analyzed retrospectively. Demographic data were recorded, and intraoperative and postoperative parameters, frailty score, geriatric nutritional risk index (GNRI), and prognostic nutritional index (PNI) were calculated. Risk factors for AKI within 7 postoperative days were investigated in accordance with the kidney disease improving global outcomes classification. Results Preoperative urea and creatinine values were significantly higher (p = .006 vs. p = .006), while hemoglobin, hematocrit, and estimated glomerular filtration rate values were significantly lower (p = .011, p = .008 vs. p = .006) in the AKI group than no AKI group. In the intraoperative period, the cardiopulmonary bypass time was longer in the AKI group (p = .031), and the need for dopamine, steradine, and red blood cells transfusion was greater (p = .026, p = .038 vs. p = .015) than no AKI group. The number of patients with a frailty score of 1–3 was significantly higher in the AKI group (p = .042). Similarly, the GNRI and PNI values, indicating nutritional status, were higher in the AKI group (p = .047 vs. p = .024). The independent risk factors for AKI were a GNRI of <91, the intraoperative need for dobutamine, preoperative serum creatinine of >1.3, and hemoglobin of <10 (p < .05). Conclusions Malnutrition and frailty are strongly associated with AKI after CABG. Clinicians can effectively predict the risk of AKI through an evaluation of frailty and nutritional scores, which can be easily calculated in the preoperative period.