NDT Advance Access originally published online on January 17, 2008
Nephrology Dialysis Transplantation 2008 23(5):1581-1587; doi:10.1093/ndt/gfm818
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N-Acetylcysteine does not artifactually lower plasma creatinine concentration
1 Department of Intensive Care, Austin Health, University of Melbourne, Australia 2 Department of Nephrology and Intensive Care, Charité University Medicine, Campus Virchow-Klinikum, Berlin, Germany 3 Division of Laboratory Medicine, Austin Health, University of Melbourne, Australia 4 Department of Critical Care, University of Pittsburgh, USA 5 Department of Intensive Care, University of Alberta, Canada 6 Department of Nephrology, Charité University Medicine, Campus Mitte, Berlin, Germany
Correspondence and offprint requests to: Rinaldo Bellomo, Director of Intensive Care Research, Austin Hospital, University of Melbourne, 3084 Heidelberg, Victoria, Australia. Tel: +61-3-94965992; Fax: +61-3-94963932; E-mail: Rinaldo.Bellomo{at}austin.org.au
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Abstract |
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Background. All randomized controlled trials of N-acetylcysteine (NAC) in contrast media-induced nephropathy used creatinine as a marker of renal function. However, it has been suggested that NAC may lower plasma creatinine levels independent of any effects on glomerular filtration rate (GFR).
Methods. At a tertiary hospital 110 cardiac surgical patients were randomly allocated to peri-operative infusion of NAC (300 mg/kg over 24 h, N = 30) or placebo (N = 80). We compared the plasma concentrations of creatinine, cystatin C and urea, the plasma creatinine/plasma cystatin C ratio and the estimated GFR at baseline and at 24 and 72 h after commencement of the infusion. We measured urinary creatinine concentration at 24 h.
Results. At baseline, the plasma creatinine/plasma cystatin C ratio did not differ between the NAC and placebo group (0.90 versus 0.92; P = 0.94). There was no significant difference in the plasma creatinine/plasma cystatin C ratio for the NAC and placebo group either during or after NAC infusion at 24 h (1.03 versus 1.00; P = 0.78) and 72 h (0.94 versus 0.89; P = 0.09). Those allocated to NAC showed no difference in urinary creatinine excretion when compared to placebo (P = 0.24).
Conclusions. The results of our study do not demonstrate that NAC artifactually lowers creatinine measured using the Jaffé method. (ClinicalTrials.gov, NCT00332631 [ClinicalTrials.gov] , NCT00334191 [ClinicalTrials.gov] )
Keywords: acute kidney injury; contrast-induced nephropathy; creatinine; cystatin C; N-acetylcysteine
Received for publication: 5. 9.07
Accepted in revised form: 19.10.07