Epidemiology of Acute Kidney Injury in the Intensive Care Unit

Table 1

Definitions of AKI.

	Serum Cr criteria	Urine output criteria
RIFLE [1]
R (Risk)	Increase in serum Cr × 1.5 or GFR decrease >25%	<0.5 mL/kg/h for 6 hours
I (Injury)	Increased serum Cr × 2 or GFR decrease >50%	<0.5 mL/kg/h for 12 hours
F (Failure)	Increase in serum Cr × 3, GFR decrease >75%, or serum Cr > 4 mg/dL	<0.3 mL/kg/h for 24 hours or anuria for 12 hours
AKIN [2]
Stage 1	Increase in serum Cr of ≥0.3 mg/dL or increase to ≥150–200% from baseline	<0.5 mL/kg/h for more than 6 hours
Stage 2	Increase in serum Cr to >200–300% from baseline	<0.5 mL/kg/h for more than 12 hours
Stage 3	Increase in serum Cr to >300% from baseline; (or serum Cr ≥ 4.0 mg/dL with an acute increase of ≥0.5 mg/dL)	<0.3 mL/kg/h for 24 hours or anuria for 12 hours