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Clinical evaluation of the new RIFLE criteria for acute renal failure


The recently proposed RIFLE classification of acute renal failure (ARF) (Acute Dialysis Quality Initiative, has yet to be evaluated in a general ICU population. RIFLE defines three grades of severity of ARF on the basis of either urine output (U) or an acute increase in serum creatinine (C): risk = C × 1.5 or U < 0.5 ml/kg/hour × 6 hours; injury = C × 2 or U < 0.5 ml/kg/hour × 12 hours; and failure = C × 3, C ≥ 4 mg/dl, U < 0.3 ml/kg/hour × 24 hours, or anuria × 12 hours.

Patients and methods

We prospectively collected data for all patients admitted to an ICU from 1 July 2000 to 30 June 2001 at the University of Pittsburgh Medical Center, a tertiary hospital with > 120 ICU beds serving medical, surgical, trauma, neurologic, and transplant patients. We tested two hypotheses: (1) increasing RIFLE class corresponds to decreasing ICU occurrence and increasing hospital mortality; and (2) patients classified by C or U criteria have similar occurrence and mortality. We classified patients according to their worst class on C or U criteria. For baseline C, we selected the lower of the admission C and the predicted C (based on age, sex, and race, using the Modification of Diet in Renal Disease formula).


A total of 5754 admissions and 5313 patients were evaluated. Occurrence and mortality are presented in Table 1.

Table 1 :


RIFLE criteria appear clinically sensible with increasing mortality. Unfortunately, C and U criteria alone yield different results, and occurrence decreases only when C criteria are used alone.

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Hoste, E., Clermont, G., Kersten, A. et al. Clinical evaluation of the new RIFLE criteria for acute renal failure. Crit Care 8, P162 (2004).

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  • Acute Renal Failure
  • Hospital Mortality
  • Urine Output
  • Tertiary Hospital
  • Anuria