A comparison of estimates of glomerular filtration in critically ill patients with augmented renal clearance

Baptista, Joao P., Udy, Andrew A., Sousa, Eduardo, Pimentel, Jorge, Wang, Lisa, Roberts, Jason A. and Lipman, Jeffrey (2011) A comparison of estimates of glomerular filtration in critically ill patients with augmented renal clearance. Critical Care, 15 3: 1-8. doi:10.1186/cc10262

Author Baptista, Joao P.
Udy, Andrew A.
Sousa, Eduardo
Pimentel, Jorge
Wang, Lisa
Roberts, Jason A.
Lipman, Jeffrey
Title A comparison of estimates of glomerular filtration in critically ill patients with augmented renal clearance
Journal name Critical Care   Check publisher's open access policy
ISSN 1364-8535
Publication date 2011-06
Sub-type Article (original research)
DOI 10.1186/cc10262
Open Access Status DOI
Volume 15
Issue 3
Start page 1
End page 8
Total pages 8
Place of publication London, England, U.K.
Publisher BioMed Central Ltd.
Collection year 2012
Language eng
Formatted abstract
Increasingly, derived estimates of glomerular filtration, such as the modification of diet in renal disease (MDRD) equation and Cockcroft-Gault (CG) formula are being employed in the intensive care unit (ICU). To date, these estimates have not been rigorously validated in those with augmented clearances, resulting in potentially inaccurate drug prescription.

Post-hoc analysis of prospectively collected data in two tertiary level ICU's in Australia and Portugal. Patients with normal serum creatinine concentrations manifesting augmented renal clearance (ARC) (measured creatinine clearance (CLCR) > 130 ml/min/1.73 m2) were identified by chart review. Comparison between measured values and MDRD and CG estimates were then undertaken. Spearman correlation coefficients (rs) were calculated to determine goodness of fit, and precision and bias were assessed using Bland-Altman plots.

Eighty-six patients were included in analysis. The median [IQR] measured CLCR was 162 [145-190] ml/min/1.73 m2, as compared to 135 [116-171], 93 [83-110], 124[102-154], and 108 [87-135] ml/min/1.73 m2 estimated by CG, modified CG, 4-variable MDRD and 6-variable MDRD formulae. All of the equations significantly under-estimated the measured value, with CG displaying the smallest bias (39 ml/min/1.73 m2). Although a moderate correlation was noted between CLCR and CG (rs = 0.26, P = 0.017) and 4-variable MDRD (rs = 0.22, P = 0.047), neither had acceptable precision for clinical application in this setting. CG estimates had the highest sensitivity for correctly identifying patients with ARC (62%).

Derived estimates of GFR are inaccurate in the setting of ARC, and should be interpreted with caution by the physician. A measured CLCR should be performed to accurately guide drug dosing.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Article number R139

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2012 Collection
School of Medicine Publications
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 53 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 0 times in Scopus Article
Google Scholar Search Google Scholar
Access Statistics: 54 Abstract Views  -  Detailed Statistics
Created: Thu, 22 Sep 2011, 11:08:56 EST by Matthew Lamb on behalf of School of Medicine