Incidence and mortality of postoperative acute kidney injury in non-dialysis patients: comparison between the AKIN and KDIGO criteria.

Objectives: This retrospective study determines whether the kidney disease: improving global outcomes (KDIGO) criteria are superior to acute kidney injury network (AKIN) criteria in detecting non-dialysis AKI events and predicting mortality in chronic kidney disease (CKD) patients after surgery.
Methods: Surgical patients who were admitted to the intensive care unit were enrolled. Non-dialysis AKI cases were defined using either KDIGO or AKIN creatinine criteria and stratified by CKD stages. The adjusted hazard ratios (AHRs) for in-hospital mortality are compared to those without AKI. The cumulative survival curves and the predictability for mortality are accessed by Kaplan-Meier method and calculating the area under the curve (AUC) for the receiver operating characteristic (ROC) curve, respectively.
Results: From a total of 826 postoperative patients, the overall in-hospital mortality rate was 11.6% (96 cases) and that for AKI according to KDIGO and AKIN criteria was 30.0% (248 cases) and 31.0% (256 cases). The cumulative survival curve stratified by CKD and AKI stages were comparable between KDIGO and AKIN criteria. The discriminative power for mortality stratified by CKD stages for KDIGO and AKIN criteria are as followed: all subjects: 0.678 versus 0.670 (both ps <0.001); non-CKD: 0.800 versus 0.809 (both ps <0.001); early-stage CKD: 0.676 versus 0.676 (both ps <0.001); late-stage CKD: 0.674 versus 0.660 (ps were <0.001 and 0.003).
Conclusion: The KDIGO criteria are superior to AKIN criteria in predicting mortality after surgery, especially in those with advanced CKD.