Cystatin C is not a better estimator of GFR than plasma creatinine in the general population.
Summary of "Cystatin C is not a better estimator of GFR than plasma creatinine in the general population."
Accurate measurement of glomerular filtration rate (GFR) is complicated and costly; therefore, GFR is commonly estimated by assessing creatinine or cystatin C concentrations. Because estimates based on cystatin C predict cardiovascular disease better than creatinine, these estimates have been hypothesized to be superior to those based on creatinine, when the GFR is near the normal range. To test this, we measured GFR by iohexol clearance in a representative sample of middle-aged (50-62 years) individuals in the general population, excluding those with coronary heart or kidney disease, stroke or diabetes mellitus. Bias, precision (median and interquartile range of estimated minus measured GFR (mGFR)), and accuracy (percentage of estimates within 30% of mGFR) of published cystatin C and creatinine-based GFR equations were compared in a total of 1621 patients. The cystatin C-based equation with the highest accuracy (94%) had a bias of 3.5 and precision of 18 ml/min per 1.73 m(2), whereas the most accurate (95%) creatinine-based equation had a bias of 2.9 and precision of 15 ml/min per 1.73 m(2). The best equation, based on both cystatin C and creatinine, had a bias of 7.6 ml/min per 1.73 m(2), precision of 15 ml/min per 1.73 m(2), and accuracy of 92%. Thus, estimates of GFR based on cystatin C were not superior to those based on creatinine in the general population. Hence, the better prediction of cardiovascular disease by cystatin C than creatinine measurements, found by others, may be due to factors other than GFR.Kidney International advance online publication, 15 September 2010; doi:10.1038/ki.2010.321.
 Clinic of Internal Medicine, Section of Nephrology, University Hospital of North Norway, Tromsø, Norway  Department of Clinical Medicine, University of Tromsø, Tromsø, Norway.
This article was published in the following journal.
Name: Kidney international
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/20844470
- DOI: http://dx.doi.org/10.1038/ki.2010.321
Medical and Biotech [MESH] Definitions
Ongoing scrutiny of a population (general population, study population, target population, etc.), generally using methods distinguished by their practicability, uniformity, and frequently their rapidity, rather than by complete accuracy.
A cystatin subtype that has a diverse tissue distribution, target specificity, and functions as an endogenous inhibitor of lysosomal cysteine proteases.
An extracellular cystatin subtype that is abundantly expressed in bodily fluids. It may play a role in the inhibition of interstitial CYSTEINE PROTEASES.
An intracellular cystatin subtype that is found in a broad variety of cell types. It is a cytosolic enzyme inhibitor that protects the cell against the proteolytic action of lysosomal enzymes such as CATHEPSINS.
Maximum Allowable Concentration
The maximum exposure to a biologically active physical or chemical agent that is allowed during an 8-hour period (a workday) in a population of workers, or during a 24-hour period in the general population, which does not appear to cause appreciable harm, whether immediate or delayed for any period, in the target population. (From Lewis Dictionary of Toxicology, 1st ed)
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