Population and study protocol
AKI
Due to the nature of the present single‐center, retrospectively designed study, the need for signed informed consent from participants was waived. Data were analyzed anonymously. The Ethics Committee of Guangdong Provincial People's Hospital approved the study according to the Declaration of Helsinki (No. GDREC2018416H).The data from patients with normal renal function at baseline who experienced AKI after cardiac surgery requiring cardiopulmonary bypass between January 1, 2006 and December 31, 2018 at the Guangdong Provincial People's Hospital (a tertiary teaching hospital) were retrospectively analyzed. There were the following exclusion criteria: renal replacement therapy before surgery; history of unilateral nephrectomy; cardiac transplantation; emergency surgery; critical status before surgery; participants hospitalized for a maximum of 2 days after the AKI episode; and serum creatinine values were not available within 1 week after the AKI episode. The estimated glomerular filtration rate (eGFR) greater than or equal to 60 mL/min × 1.72 m