DISCUSSION
AKI, proteinuria, chronic kidney disease, diabetes
HYPERTENSION, CORONARY HEART DISEASE, DIABETES
A model for predicting persistent AKI after cardiac surgery in patients with normal baseline renal function who experienced AKI after cardiac surgery was developed using routinely collected clinical data. The model was also evaluated based on its discrimination, calibration, and clinical utility in the validation group. To the best of our knowledge, this is the first study to develop and validate a model for predicting persistent AKI after cardiac surgery. The new model may aid the reevaluation and clinical management of patients with AKI after cardiac surgery to reduce the chance of chronic kidney disease and improve prognosis.Some scholars call for clinicians to pay more attention to persistent AKI, since it is more consistent with what clinicians understand as the true “clinical AKI”.Limited data on the rate of persistent AKI after cardiac surgery were reported in previous studies. The occurrence rate of persistent AKI fluctuated from 10.4% to 71.4% in limited number of previous studies due to different diagnostic criteria and study populations.Several predictors, such as age, hypertension, diabetes, coronary heart disease, postoperative IABP use, and AKI stage at the initial diagnosis of AKI, were risk factors for persistent AKI in previous reports.Admittedly, the present study had some limitations. First, even though the sample size was relatively large, the model needs to be verified at other independent centers since it was a single‐center study. Second, data were missing for some variables. Multiple imputation was used to minimize the effect of missing data on model performance as recommended by previous reports. Finally, data for some variables, such as proteinuria and hemodynamic variables before or at the initial diagnosis of AKI after cardiac surgery, were not obtained due to the retrospective nature of the study. The influence of these variables on the model's performance was unknown. For the same reason, aortic cross‐clamp time, surgical anesthesia duration, and intraoperative use of red blood cells and platelets were not analyzed. Fortunately, the model developed using the available data showed a good performance.