A Comparison of Acute Kidney Injury Classifications in Patients With Severe Sepsis and Septic Shock

Introduction: Acute kidney injury (AKI) is a common and serious complication in patients with severe sepsis and septic shock. AKI can be classified using the RIFLE (Risk, Injury, Failure, Loss and End-stage) and/or the Acute Kidney Injury Network (AKIN) criteria. The aim of this study was to determine which of the 2 systems better predicted 28-day mortality in patients with severe sepsis and septic shock. Methods: We retrospectively examined the medical records of all patients with severe sepsis and septic shock who were admitted to our medical intensive care unit (ICU) between January 2005 and December 2006 and compared the ability of the RIFLE and AKIN criteria to predict mortality. Results: Of the 326 patients admitted during the study period, 291 were included. AKI 48 and 72 hours after ICU admission was observed in 62.9% and 55.5% of patients, respectively, according to RIFLE criteria and in 65.6% and 59.2%, respectively, according to AKIN criteria. The overall 28-day mortality rate was 48.5%, and mortality was significantly associated with the severity of AKI, by both RIFLE and AKIN criteria. Both criteria had a similar ability to predict 28-day mortality 48 hours (0.65-69, P < 0.01) and 72 hours (0.66-70, P < 0.01) after ICU admission. Conclusions: The incidence of AKI in patients with sepsis and septic shock was slightly higher using AKIN than RIFLE criteria. However, using the AKIN criteria did not enhance the ability of AKI to predict 28-day mortality in such patients.