Incidence and Risk Factors of Postoperative Acute Kidney Injury in Non-Cardiovascular Surgery: A Retrospective Cohort Study

Objective: To identify the incidence, risk factors, and outcome of postoperative acute kidney injury (AKI) in non-cardiovascular surgery. Materials and Methods: A single-center retrospective cohort study included patients who underwent non-cardiovascular surgeries such as general, orthopedics, gynecology, neurosurgery, ENT, plastic, and endoscopy, between January 1, 2019 and December 31, 2020. The primary outcome was the incidence of AKI within seven days after surgery, as defined by the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. The secondary outcomes were risk factors and the outcome of AKI. Results: From 2,898 cases, the incidence of postoperative AKI was 2% (57 cases). Twenty-two out of 57 cases (38.6%) had diagnosis of acute renal failure in the discharge summary. Independent risk factors of postoperative AKI by multivariate logistic regression analysis were the American Society of Anesthesiologists (ASA) classification of 3 or greater, emergency surgery, atrial fibrillation, preoperative use of a mechanical ventilator, eGFR of less than 60 mL/minute/1.73 m², hypoalbuminemia, intraoperative urine output of less than 0.5 mL/kg/hour, vasopressor infusion, and intraoperative blood transfusion. Patients with postoperative AKI had higher mortality rates and postoperative complications included pneumonia, surgical site infection, sepsis, respiratory failure, and severe arrhythmia. Conclusion: Postoperative renal function should be monitored in patients with risk factors associated with postoperative AKI to improve patient outcomes.