Data collection and definition
AKI, coronary atherosclerotic heart disease, postoperative AKI, diabetes
HYPERTENSION, DIABETES
The data for patients were extracted from the electronic medical record system of our hospital. Based on previous literature review and clinical expertise, the following candidate predictors were considered: demographic characteristics, comorbidities (hypertension, diabetes, and coronary atherosclerotic heart disease), history of heart surgery, baseline serum creatinine level, preoperative left ventricular ejection fraction (LVEF), cardiac surgery type, cardiopulmonary bypass time, AKI stage at the initial diagnosis of AKI after cardiac surgery, postoperative medication use, laboratory test results after surgery, duration of postoperative mechanical ventilation, postoperative intra‐aortic balloon pump (IABP) use, and reoperation status. AKI stage at the initial diagnosis of AKI after cardiac surgery was classified by the KDIGO criteria upon first AKI diagnosis after surgery. Postoperative variable data, such as postoperative medication use, laboratory test results after surgery, and reoperation status, were collected from the time after cardiac surgery to the time at first diagnosis of postoperative AKI. If more than one laboratory test result was available after surgery, the latest result before the time of the initial diagnosis of AKI after cardiac surgery was analyzed. Previous cardiac surgery was defined as the cardiac surgery was underwent before January 1, 2006.