Pitfalls of using estimations of glomerular filtration rate in an intensive care population

Martin, Jennifer H., Fay, Michael F., Udy, Andrew, Roberts, Jason, Kirkpatrick, Carl, Ungerer, Jacobus and Lipman, Jeffrey (2011) Pitfalls of using estimations of glomerular filtration rate in an intensive care population. Internal Medicine Journal, 41 7: 537-543. doi:10.1111/j.1445-5994.2009.02160.x


Author Martin, Jennifer H.
Fay, Michael F.
Udy, Andrew
Roberts, Jason
Kirkpatrick, Carl
Ungerer, Jacobus
Lipman, Jeffrey
Title Pitfalls of using estimations of glomerular filtration rate in an intensive care population
Journal name Internal Medicine Journal   Check publisher's open access policy
ISSN 1445-5994
1444-0903
Publication date 2011-07
Year available 2010
Sub-type Article (original research)
DOI 10.1111/j.1445-5994.2009.02160.x
Open Access Status
Volume 41
Issue 7
Start page 537
End page 543
Total pages 7
Editor Michael O’Leary
Place of publication Richmond, VIC, Australia
Publisher Wiley-Blackwell Publishing Asia
Collection year 2011
Language eng
Abstract Article first published online: 4 January 2010
Formatted abstract
Background:
Accurate knowledge of the glomerular filtration rate (GFR) is imperative in the intensive care unit (ICU) as renal status is important for medical decisions including drug dosing. Recently, an estimation of GFR (eGFR) was suggested as a method of estimating GFR. How well this formula predicts GFR in unwell patients with normal initial serum creatinine concentrations has not been examined.

Methods:
The accuracy of the eGFR (before and after adjustment for actual body surface area (BSA)) was compared with measured and with estimated creatinine clearance using the Cockcroft Gault (CG) formula adjusted for total and lean body weight.

Results:
237 observations were recorded in 47 subjects. These were initially analysed independently, and then using the first observation only. Overall the mean difference between measured creatinine clearance and eGFR was -12ml/min (95% CI -20 to -3), between measured creatinine clearance and CG + 17ml/min (95% CI 9 to 24), between measured creatinine clearance and CG adjusted for ideal body weight +12 ml/min (95% CI 4 to 21) and between measured creatinine clearance and eGFR 'unadjusted' for BSA 5ml/min (95% CI -2 to 13).

Conclusions:
Using either eGFR or CG formulae to estimate renal function in ICU subjects with normal serum creatinine concentrat ions is inaccurate. Although correcting for BSA improves the eGFR, this requirement to measure height and weight removes a major attraction for its use. We suggest that eGFR should not be automatically calculated in the ICU setting.

Keyword eGFR
Renal Function
GFR
Intensive Care
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Article first published online: 4 January 2010

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2011 Collection
UQ Diamantina Institute Publications
 
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Created: Wed, 07 Apr 2010, 15:23:27 EST by Fiona Mactaggart on behalf of UQ Diamantina Institute