Acute kidney injury as defined by the RIFLE criteria is a risk factor for kidney transplant graft failure.

Acute kidney injury (AKI) is not recognized as a major complication at the maintenance phase after kidney transplantation (KTx). Moreover, it is not clear whether the onset of AKI leads to graft failure. We examined the incidence of AKI that developed three months or later after KTx at our institute. We examined whether the incidence of AKI defined by the Risk of renal dysfunction, Injury to the kidney, Failure of kidney function, Loss of kidney function and End-stage kidney disease criteria associates with graft failure by matched-pair Cox regression analysis. A total of 289 patients were available for the final analysis. The overall incidence of AKI was 20.4%, and the common etiology of AKI was bacterial infectious diseases. The group that developed AKI had significantly lower graft survival than non-AKI group independently of acute rejection. AKI Risk represented a high risk for graft failure and AKI Injury/Failure represented a higher risk for graft failure. The analysis by the AKIN classification yielded the similar results. These results indicate that AKI is a relatively common complication of KTx and represents the major risk for graft failure. We should make every effort in the prevention and early detection to avoid the occurrence of AKI and the subsequent graft failure after KTx.