Significant differences when using creatinine, modification of diet in renal disease, or cystatin C for estimating glomerular filtration rate in ICU patients.
BACKGROUND
Renal dysfunction is associated with increased morbidity and mortality in intensive care patients. In most cases the glomerular filtration rate (GFR) is estimated based on serum creatinine and the Modification of Diet in Renal Disease (MDRD) formula, but cystatin C-estimated GFR is being used increasingly. The aim of this study was to compare creatinine and MDRD and cystatin C-estimated GFR in intensive care patients.


METHODS
Retrospective observational study was performed, on patients treated within the general intensive care unit (ICU) during 2004-2006, in a Swedish university hospital.


RESULTS
GFR markers are frequently ordered in the ICU; 92% of the patient test results had cystatin C-estimated GFR (eGFR(cystatinC)) ≤ 80 mL/min/1.73 m(2), 75% had eGFR ≤ 50 mL/min/1.73 m(2), and 30% had eGFR ≤ 20 mL/min/1.73 m(2). In contrast, only 46% of the patients had reduced renal function assessed by plasma creatinine alone, and only 47% had eGFR(MDRD) ≤ 80 mL/min/1.73 m(2). The mean difference between eGFR(MDRD) and eGFR(cystatinC) was 39 mL/min/1.73 m(2) for eGFR(cystatinC) values ≤ 60 mL/min/1.73 m(2).


CONCLUSIONS
GFR is commonly assessed in the ICU. Cystatin C-estimated GFR yields markedly lower GFR results than plasma creatinine and eGFR(MDRD). Many pharmaceuticals are eliminated by the kidney, and their dosage is adjusted for kidney function. Thus, the differences in GFR estimates by the methods used indicate that the GFR method used in the intensive care unit may influence the treatment.
Section of Anaesthesiology & Critical Care, Department of Surgical Sciences, Uppsala University Hospital, Uppsala, Sweden. mlipcsey@eml.cc
Miklós
M
Lipcsey
Mia
M
Furebring
Sten
S
Rubertsson
Anders
A
Larsson
D000328:Adult; D000368:Aged; D003404:Creatinine / Q000097:blood*; D055316:Cystatin C / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007362:Intensive Care Units; D007677:Kidney Function Tests / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
D055316:Cystatin C; D003404:Creatinine