Contribution of acute kidney injury toward morbidity and mortality in burns: A contemporary analysis

Background: Severe acute kidney injury (AKI) that requires dialytic support, a relatively uncommon complication in severely burned adults, is associated with a substantially increased mortality rate. It is not known whether milder forms of AKI have prognostic importance in burns. Methods: We performed an observational cohort analysis of consecutive patients with major burns admitted to the burn care unit of a tertiary-care center from 1998 to 2003. Our main outcome measures were AKI stratified by the Risk of renal dysfunction, Injury to the kidney, Failure of kidney function, Loss of kidney function, and End-stage kidney disease (RIFLE) classification and mortality. Results: AKI occurred in 81 of 304 patients (26.6%) with burns on 10% or greater total-body surface area. Risk factors for AKI on multivariate analysis were inhalational injury, catheter infection, and sepsis. Patients with AKI stratified by using the RIFLE classification had greater mortality, greater requirement of artificial ventilation, and longer durations of intensive care unit and hospital stays. Mortality was not significantly different among those with the "Risk" and "Injury" strata of RIFLE AKI compared with those without AKI, but mortality increased significantly with the "Failure" (60%) strata. In multivariate analysis, age, greater total-body surface area, inhalational injury, and the RIFLE classification of Failure were each independent predictors of death. Conclusion: In conclusion, the mortality of patients with burns with severe AKI remains high and unchanged in the modern era of critical care medicine. The RIFLE classification added prognostic information regarding morbidity in patients with milder forms of AKI.