Acute renal failure: mortality was high.

Clinical bottom line (level 4)

  1. The commonest causes of acute renal failure were acute tubular necrosis (45%), prerenal failure (21%), acute onset chronic renal failure (13%) and obstruction (10%). Other causes were rare.
  2. Death was common with acute renal failure (~50%).
  3. Patients were at increased risk of dying if they:
    • were ventilated (NNH = 2 at unknown)
    • had sustained hypotension (NNH = 3 at unknown)
    • required dialysis (NNH = 4 at unknown)
    • were jaundiced on admission (NNH = 4 at unknown)
    • had oliguria on admission (NNH = 6 at unknown)
  4. A third of patients required dialysis at some point, but few went on to require it long term.
Liano et al: Kidney International 1996; 50: 811-818
Expires July 2003

The study

Inception cohort study with objective outcomes, not adjusted for confounding factors, not validated in an independent set of patients.

Setting: 13 tertiary care hospitals, Spain

748 patients (aged range 15 to 95 years; mean 64, 65% male) acute renal failure (either on admission or developing during their hospital stay), defined as one of the following:
  • sudden increase in creatinine 177 µ mol/l or more with prior normal renal function
  • increased creatinine on admission with at least 50% recovery prior to discharge
  • increased creatinine on admission with no suspicion of chronic renal failure and normal or enlarged renal size
  • mild-to-moderate chronic renal failure (creatinine <267 µ mol/l) with sudden 50% increase in creatinine


Excluded if
  • chronic renal failure (defined as baseline creatinine >267 µ mol/l)



    • Factors studied:
  • death, dialysis
  • ventilated at admission
  • sustained hypotension at admission
  • dialysed
  • jaundice at admission
  • oliguria at admission




    • Univariate analysis was performed on risk factors.

    100% followed for until discharge (mean 30 days)
    Outcomes studied:
  • mortality
  • dialysis
  • long term dialysis
  • acute tubular necrosis
  • prerenal
  • acute onset chronic renal failure
  • obstructive (stones, prostate, tumour)
  • acute tubulointerstitial nephritis
  • secondary glomerulonephritis
  • primary glomerulonephritis
  • vasculitis
  • vascular (atheroembolic or thrombosis)
  • other or unknown

    • Forty-six patients studied underwent a renal biopsy for diagnosis. Clinical indications for renal biopsy were not explicitly defined.

    The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)
    mortality until discharge (mean 30 days) 337/748 45%
    (41% to 49%)
    dialysis until discharge (mean 30 days) 270/748 36%
    (33% to 40%)
    long term dialysis until discharge (mean 30 days) 8/748 1.1%
    (0.33% to 1.8%)
    acute tubular necrosis until discharge (mean 30 days) 337/748 45%
    (41% to 49%)
    prerenal until discharge (mean 30 days) 158/748 21%
    (18% to 24%)
    acute onset chronic renal failure until discharge (mean 30 days) 95/748 13%
    (10% to 15%)
    obstructive (stones, prostate, tumour) until discharge (mean 30 days) 75/748 10%
    (7.9% to 12%)
    acute tubulointerstitial nephritis until discharge (mean 30 days) 15/748 2.0%
    (1.0% to 3.0%)
    secondary glomerulonephritis until discharge (mean 30 days) 12/748 1.6%
    (0.70% to 2.5%)
    primary glomerulonephritis until discharge (mean 30 days) 11/748 1.5%
    (0.61% to 2.3%)
    vasculitis until discharge (mean 30 days) 11/748 1.5%
    (0.61% to 2.3%)
    vascular (atheroembolic or thrombosis) until discharge (mean 30 days) 8/748 1.1%
    (0.33% to 1.8%)
    other or unknown until discharge (mean 30 days) 26/748 3.5%
    (2.2% to 4.8%)

    prognostic factor for
    mortality     		time to outcome unadjusted RR
    (95% CI)    		 NNF+
    (95% CI)
    ventilated at admission until discharge (mean 30 days) 2.52
    (2.19 to 2.91)     		2
    (2 to 3)
    sustained hypotension at admission until discharge (mean 30 days) 2.08
    (1.79 to 2.41)     		3
    (2 to 4)
    dialysed until discharge (mean 30 days) 1.98
    (1.70 to 2.31)     		3
    (2 to 4)
    jaundice at admission until discharge (mean 30 days) 1.66
    (1.42 to 1.94)     		4
    (3 to 6)
    oliguria at admission until discharge (mean 30 days) 1.46
    (1.23 to 1.74)     		6
    (4 to 12)

    Comments

    1. Death rate from renal failure was higher in ICU patients (70%) compared with medical or surgical patients (40%) or nephrology patients (19%).
    2. Though a third of patients in this study required dialysis, only 8 patients (1% of all patients, 2% of survivors) required chronic haemodialysis.
    3. The hospitals involved in this study were all tertiary care institutions- this may lead to over-representation of severe problems and patients with poorer prognoses.
    4. The epidemiology of ARF is likely to be similar in most developed countries.

    Citation

    1. Liano F, Pascual J, The Madrid Acute Renal Failure Study Group : Epidemiology of acute renal failure: a prospective, multicenter, community-based study. Kidney International 1996; 50: 811-818
    Search Terms: bibliographic reference
    Contributor: Catherine Clase, Chris Ball and Clare Wotton, April 2000
    Reviewer: Mohammad Saklayen

    Clinical Question.
    Patient acute renal failure
    Intervention or Exposure prognostic factors
    Outcome mortality