A multi-centre evaluation of the RIFLE criteria for early acute kidney injury in critically ill patients.
BACKGROUND
The Acute Dialysis Quality Initiative Working Group recently developed the RIFLE criteria, a consensus definition for acute kidney injury (AKI). We sought to evaluate the RIFLE criteria on the day of ICU admission in a large heterogenous population of critically ill patients.


METHODS
Retrospective interrogation of prospectively collected data from the Australian New Zealand Intensive Care Society Adult Patient Database. We evaluated 120 123 patients admitted for >/=24 h from 1 January 2000 to 31 December 2005 from 57 ICUs across Australia.


RESULTS
The median (IQR) age was 64.3 (50.8-75.4) years, 59.5% were male, 28.6% had co-morbid disease, 50.3% were medical admissions and the initial mean (+/-SD) APACHEII score was 16.9 (+/-7.7). According to the RIFLE criteria, on the day of admission, AKI occurred in 36.1%, with a maximum RIFLE category of Risk in 16.3%, Injury in 13.6%, and Failure 6.3%. AKI, defined by any RIFLE category, was associated with an increase in hospital mortality (OR 3.29, 95% CI 3.19-3.41, P < 0.0001). The crude hospital mortality stratified by RIFLE category was 17.9% for Risk, 27.7% for Injury and 33.2% for Failure. By multivariable analysis, each RIFLE category was independently associated with hospital mortality (OR: Risk 1.58, Injury 2.54 and Failure 3.22).


CONCLUSIONS
In a large heterogenous cohort of critically ill patients, the RIFLE criteria classified >36% with AKI on the day of admission. For successive increases in severity of RIFLE category, there were increases in hospital mortality. The RIFLE criteria represent a simple tool for the detection and classification of AKI and for correlation with clinical outcomes.
Bagshaw
Sean M
SM
Division of Critical Care Medicine, University of Alberta Hospital, 3C1.16 Walter C. Mackenzie Centre, 8440-122 Street, Edmonton, Alberta T6G2B7, Canada. bagshaw@ualberta.ca
George
Carol
C
Dinu
Irina
I
Bellomo
Rinaldo
R
D018806:APACHE; D058186:Acute Kidney Injury / Q000145:classification* / Q000401:mortality / Q000628:therapy; D000368:Aged; D016638:Critical Illness / Q000401:mortality / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D017052:Hospital Mortality / Q000639:trends; D006801:Humans; D007362:Intensive Care Units / Q000592:standards*; D007902:Length of Stay / Q000639:trends; D008297:Male; D008875:Middle Aged; D010351:Patient Discharge / Q000639:trends; D011785:Quality Assurance, Health Care / Q000379:methods*; D006435:Renal Dialysis / Q000592:standards*; D012189:Retrospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D013997:Time Factors; D014739:Victoria / Q000453:epidemiology