Four hour creatinine clearance is better than plasma creatinine for monitoring renal function in critically ill patients

Crit Care. 2012 Jun 19;16(3):R107. doi: 10.1186/cc11391.


Introduction: Acute kidney injury (AKI) diagnosis is based on an increase in plasma creatinine, which is a slowly changing surrogate of decreased glomerular filtration rate. We investigated whether serial creatinine clearance, a direct measure of the glomerular filtration rate, provided more timely and accurate information on renal function than serial plasma creatinine in critically ill patients.

Methods: Serial plasma creatinine and 4-hour creatinine clearance were measured 12-hourly for 24 hours and then daily in 484 patients. AKI was defined either as > 50% increase in plasma creatinine from baseline, or > 33.3% decrease in creatinine clearance. The diagnostic and predictive performance of the two AKI definitions were compared.

Results: Creatinine clearance decrease diagnosed AKI in 24% of those not diagnosed by plasma creatinine increase on entry. These patients entered the ICU sooner after insult than those diagnosed with AKI by plasma creatinine elevation (P = 0.0041). Mortality and dialysis requirement increased with the change in creatinine clearance-acute kidney injury severity class (P = 0.0021). Amongst patients with plasma creatinine < 1.24 mg/dl on entry, creatinine clearance improved the prediction of AKI considerably (Net Reclassification Improvement 83%, Integrated Discrimination Improvement 0.29). On-entry, creatinine clearance associated with AKI severity and duration (P < 0.0001) predicted dialysis need (area under the curve: 0.75) and death (0.61). A > 33.3% decrease in creatinine clearance over the first 12 hours was associated with a 2.0-fold increased relative risk of dialysis or death.

Conclusions: Repeated 4-hour creatinine clearance measurements in critically ill patients allow earlier detection of AKI, as well as progression and recovery compared to plasma creatinine.

Trial registration: Australian New Zealand Clinical Trials Registry ACTRN012606000032550.

Publication types

  • Clinical Trial
  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Kidney Injury / blood*
  • Acute Kidney Injury / diagnosis
  • Acute Kidney Injury / epidemiology
  • Adult
  • Aged
  • Biomarkers / blood
  • Cohort Studies
  • Creatinine / blood*
  • Critical Illness / epidemiology
  • Critical Illness / therapy*
  • Female
  • Humans
  • Kidney Function Tests / methods*
  • Male
  • Metabolic Clearance Rate / physiology
  • Middle Aged
  • New Zealand / epidemiology
  • Registries
  • Time Factors


  • Biomarkers
  • Creatinine

Associated data

  • ANZCTR/ACTRN012606000032550