Acute renal failure: acute tubular necrosis: sex, clinical history and oliguria were predictors of mortality.

Clinical bottom line (level 2b)

  1. A third of patients with acute renal failure died, and over half required dialysis.
  2. Patients were more likely to die if they:
    • have an acute MI (NNF = 2 for 60 days)
    • have a stroke or seizure (NNF = 2 for 60 days)
    • have chronic immunosuppression (NNF = 2 for 60 days)
    • have oliguria (NNF = 3 for 60 days)
    • are male (NNF = 3 for 60 days)
    • are on mechanical ventilation (NNF = 4 for 60 days)
  3. Patients were less likely to die if they have a history of hypertension (NNF = -6 for 60 days) .
Chertow et al: Journal of the American Society of Nephrology 1998; 9: 692-698
Expires July 2003

The study

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

Setting: 59 clinical centres, USA and Canada

256 patients (aged mean 62 years, 65% male) adults with acute renal failure (rise in serum creatinine of = 88 µ mol/l in a 48 hour period) due to acute tubular necrosis (diagnosed based on clinical histories and laboratory findings-ultrasound, urine microscopy, fractional excretion of sodium) who were assigned to the control arm of a randomised controlled trial of anaritide.

Excluded if
  • prerenal azotaemia
  • vascular obstruction
  • obstruction
  • systemic or intrinsic renal disease other than acute tubular necrosis
  • dialysis during current episode of acute renal failure
  • systolic blood pressure <90 mmHg despite the use of vasopressor therapy
  • expected to require dialysis within 24 hours
  • not candidates for dialysis
  • underlying medical conditions of such severity that an improvement in renal function would not be expected to improve clinical outcome
  • prior renal transplantation
  • severe chronic renal insufficiency (creatinine >264 µ mol/l)



    • Factors studied:
  • death, dialysis
  • acute MI
  • acute stroke or seizure
  • oliguria
  • male
  • mechanical ventilation
  • history of hypertension




    • Logistic regression analysis was performed to adjust for confounding factors.

    99% followed for 60 days
    Outcomes studied:
  • death
  • death or needed dialysis

    • The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)
    death 60 days 93/256 36%
    (30% to 42%)
    death or needed dialysis 60 days 145/256 57%
    (51% to 63%)

    prognostic factor for
    death     		time to outcome control rate (%) adjusted OR
    (95% CI)    		 NNF+
    (95% CI)
    acute MI 60 days 93/256
    (36%)     		5.90
    (2.43 to 14.4)     		2
    (2 to 5)
    acute stroke or seizure 60 days 93/256
    (36%)     		7.35
    (1.92 to 28.1)     		2
    (2 to 6)
    oliguria 60 days 93/256
    (36%)     		4.39
    (2.09 to 9.24)     		3
    (2 to 6)
    male 60 days 93/256
    (36%)     		3.70
    (1.75 to 7.82)     		3
    (2 to 7)
    mechanical ventilation 60 days 93/256
    (36%)     		2.95
    (1.53 to 5.68)     		4
    (2 to 10)
    history of hypertension 60 days 93/256
    (36%)     		0.44
    (0.23 to 0.86)     		-6
    (-29 to -4)

    • Oliguria, acute MI, mechanical ventilation and arrhythmias are prognostic factors for death or dialysis. Age is not a predictive factor for death.

    Comments

    1. Numbers needed to follow may be overestimated due to the overall control rate being used to calculate them.
    2. The nature of this analysis on the control arm of an RCT may account for the patient population being skewed to the seriously ill.
    3. No adjustment for the type of dialysis membrane has been made (a known prognostic factor for death).

    Citation

    1. Chertow GM, Lazarus JM, Paganni EP, et al: Predictors of mortality and the provision of dialysis in patients with acute tubular necrosis. Journal of the American Society of Nephrology 1998; 9: 692-698
    Contributor: Catherine Clase, Chris Ball and Clare Wotton, April 2000
    Reviewer: Harold Szerlip

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