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Comparative Study
. 2014 Jun;29(6):1195-203.
doi: 10.1093/ndt/gft509. Epub 2014 Jan 20.

Glomerular filtration rate estimation using cystatin C alone or combined with creatinine as a confirmatory test

Li Fan  1 , Lesley A Inker  1 , Jerome Rossert  2 , Marc Froissart  3 , Peter Rossing  4 , Michael Mauer  5 , Andrew S Levey  1
Affiliations
Comparative Study

Glomerular filtration rate estimation using cystatin C alone or combined with creatinine as a confirmatory test

Li Fan et al. Nephrol Dial Transplant. 2014 Jun.

Abstract

Background: Glomerular filtration rate (GFR) estimating equations using the combination of creatinine and cystatin C (eGFRcr-cys) are more accurate than equations using either alone (eGFRcr or eGFRcys). New guidelines suggest measuring cystatin C as a confirmatory test when eGFRcr may be inaccurate, but do not specify demographic or clinical conditions in which eGFRcys or eGFRcr-cys are more accurate than eGFRcr nor which estimate to use in such circumstances.

Methods: We compared the performance of the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations in 1119 subjects in the CKD-EPI cystatin C external validation dataset. Subgroups were defined by eGFRcr, age, sex, diabetes status and body mass index (BMI). The reference test was GFR measured using urinary or plasma clearance of exogenous filtration markers. Cystatin C and creatinine assays were traceable to primary reference materials. Accuracy was defined as the absolute difference in eGFR compared with mGFR.

Results: The mean mGFR was 70 ± 41 (SD) mL/min/1.73 m(2). eGFRcys was more accurate than eGFRcr at lower BMI and less accurate at higher BMI, especially at higher levels of eGFRcr. There were small differences in accuracy in people according to the diabetes status. eGFRcr-cys was as accurate or more accurate than eGFRcr or eGFRcys in these and all other subgroups.

Conclusions: eGFRcr-cys, but not eGFRcys, is more accurate than eGFRcr in most subgroups we studied, suggesting preferential use of eGFRcr-cys when serum cystatin C is measured as a confirmatory test to obtain more accurate eGFR. Further studies are necessary to evaluate diagnostic strategies for using eGFRcys and eGFRcr-cys.

Keywords: CKD-EPI; cystatin C; diagnostic test accuracy; estimated GFR.

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Figures

FIGURE 1:
FIGURE 1:
Bias of eGFRcr by demographic and clinical characteristics of subgroups. Bias is calculated as the mean value of (mGFR − eGFRcr). eGFRcr, estimated glomerular filtration rate based on serum creatinine; mGFR, measured glomerular filtration rate.
FIGURE 2:
FIGURE 2:
Bias of eGFRcys by demographic and clinical characteristics of subgroups. Bias is calculated as the mean value of (mGFR − eGFRcys). eGFRcys, estimated glomerular filtration rate based on serum cystatin C; eGFRcr, estimated glomerular filtration rate based on serum creatinine; mGFR, measured glomerular filtration rate.
FIGURE 3:
FIGURE 3:
Bias of eGFRcr-cys by demographic and clinical characteristics of subgroups. Bias is calculated as the mean value of (mGFR − eGFRcr-cys). eGFRcr-cys, estimated glomerular filtration rate based on serum creatinine and cystatin C; eGFRcr, estimated glomerular filtration rate based on serum creatinine; mGFR, measured glomerular filtration rate.
See this image and copyright information in PMC

References

    1. Inker LA, Schmid CH, Tighiouart H, et al. Estimating glomerular filtration rate from serum creatinine and cystatin C. N Engl J Med. 2012;367:20–29. - PMC - PubMed
    1. Ma YC, Zuo L, Chen JH, et al. Improved GFR estimation by combined creatinine and cystatin C measurements. Kidney Int. 2007;72:1535–1542. - PubMed
    1. Anderson AH, Yang W, Hsu CY, et al. Estimating GFR among participants in the Chronic Renal Insufficiency Cohort (CRIC) Study. Am J Kidney Dis. 2012;60:250–261. - PMC - PubMed
    1. Eriksen BO, Mathisen UD, Melsom T, et al. Cystatin C is not a better estimator of GFR than plasma creatinine in the general population. Kidney Int. 2010;78:1305–1311. - PubMed
    1. Schaeffner ES, Ebert N, Delanaye P, et al. Two novel equations to estimate kidney function in persons aged 70 years or older. Ann Intern Med. 2012;157:471–481. - PubMed

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