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Accuracy of GFR estimating equations combining standardized cystatin C and creatinine assays: a cross-sectional study in Sweden

Björk, Jonas LU ; Grubb, Anders LU ; Larsson, Anders; Hansson, Lars-Olof; Flodin, Mats; Sterner, Gunnar LU ; Lindström, Veronica LU and Nyman, Ulf LU (2015) In Clinical Chemistry and Laboratory Medicine 53(3). p.403-414
Abstract
Background: The recently established international cystatin C calibrator makes it possible to develop non-laboratory specific glomerular filtration rate (GFR) estimating (eGFR) equations. This study compares the performance of the arithmetic mean of the revised Lund-Malmo creatinine and CAPA cystatin C equations (MEAN(LM-REV+CAPA)), the arithmetic mean of the Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI) creatinine and cystatin C equations (MEAN(CKD-EPI)), and the composite CKD-EPI equation (CKD-EPICREA+CYSC) with the corresponding single marker equations using internationally standardized calibrators for both cystatin C and creatinine. Methods: The study included 1200 examinations in 1112 adult Swedish patients... (More)
Background: The recently established international cystatin C calibrator makes it possible to develop non-laboratory specific glomerular filtration rate (GFR) estimating (eGFR) equations. This study compares the performance of the arithmetic mean of the revised Lund-Malmo creatinine and CAPA cystatin C equations (MEAN(LM-REV+CAPA)), the arithmetic mean of the Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI) creatinine and cystatin C equations (MEAN(CKD-EPI)), and the composite CKD-EPI equation (CKD-EPICREA+CYSC) with the corresponding single marker equations using internationally standardized calibrators for both cystatin C and creatinine. Methods: The study included 1200 examinations in 1112 adult Swedish patients referred for measurement of GFR (mGFR) 2008-2010 by plasma clearance of iohexol (median 51 mL/min/1.73 m(2)). Bias, precision (interquartile range, IQR) and accuracy (percentage of estimates +/- 30% of mGFR; P-30) were compared. Results: Combined marker equations were unbiased and had higher precision and accuracy than single marker equations. Overall results of MEAN(LM-REV+CAPA)/MEAN(CKD-EPI)/CKD-EPICREA+CYSC were: median bias -2.2%/-0.5%/-1.6%, IQR 9.2/9.2/8.8 mL/min/1.73 m(2), and P-30 91.3%/91.0%/91.1%. The P-30 figures were about 7-14 -percentage points higher than the single marker equations. The combined equations also had a more stable performance across mGFR, age and BMI intervals, generally with P-30 >= 90% and never <80%. Combined equations reached P-30 of 95% when the difference between eGFR(CREA) and eGFR(CYSC) was <10% but decreased to 82% at a difference of >= 40%. Conclusions: Combining cystatin C and creatinine assays improves GFR estimations with P-30 >= 90% in adults. Reporting estimates of both single and combined marker equations in clinical settings makes it possible to assess the validity of the combined equation based on the agreement between the single marker equations. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
chronic kidney disease, creatinine, cystatin C, glomerular filtration, rate, kidney function tests
in
Clinical Chemistry and Laboratory Medicine
volume
53
issue
3
pages
403 - 414
publisher
De Gruyter
external identifiers
  • wos:000349558500017
  • scopus:84923116110
ISSN
1434-6621
DOI
10.1515/cclm-2014-0578
language
English
LU publication?
yes
id
757b823a-82c9-4257-86e9-9777cbddbd1d (old id 5160203)
date added to LUP
2015-04-01 07:39:40
date last changed
2017-10-29 03:23:36
@article{757b823a-82c9-4257-86e9-9777cbddbd1d,
  abstract     = {Background: The recently established international cystatin C calibrator makes it possible to develop non-laboratory specific glomerular filtration rate (GFR) estimating (eGFR) equations. This study compares the performance of the arithmetic mean of the revised Lund-Malmo creatinine and CAPA cystatin C equations (MEAN(LM-REV+CAPA)), the arithmetic mean of the Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI) creatinine and cystatin C equations (MEAN(CKD-EPI)), and the composite CKD-EPI equation (CKD-EPICREA+CYSC) with the corresponding single marker equations using internationally standardized calibrators for both cystatin C and creatinine. Methods: The study included 1200 examinations in 1112 adult Swedish patients referred for measurement of GFR (mGFR) 2008-2010 by plasma clearance of iohexol (median 51 mL/min/1.73 m(2)). Bias, precision (interquartile range, IQR) and accuracy (percentage of estimates +/- 30% of mGFR; P-30) were compared. Results: Combined marker equations were unbiased and had higher precision and accuracy than single marker equations. Overall results of MEAN(LM-REV+CAPA)/MEAN(CKD-EPI)/CKD-EPICREA+CYSC were: median bias -2.2%/-0.5%/-1.6%, IQR 9.2/9.2/8.8 mL/min/1.73 m(2), and P-30 91.3%/91.0%/91.1%. The P-30 figures were about 7-14 -percentage points higher than the single marker equations. The combined equations also had a more stable performance across mGFR, age and BMI intervals, generally with P-30 &gt;= 90% and never &lt;80%. Combined equations reached P-30 of 95% when the difference between eGFR(CREA) and eGFR(CYSC) was &lt;10% but decreased to 82% at a difference of &gt;= 40%. Conclusions: Combining cystatin C and creatinine assays improves GFR estimations with P-30 &gt;= 90% in adults. Reporting estimates of both single and combined marker equations in clinical settings makes it possible to assess the validity of the combined equation based on the agreement between the single marker equations.},
  author       = {Björk, Jonas and Grubb, Anders and Larsson, Anders and Hansson, Lars-Olof and Flodin, Mats and Sterner, Gunnar and Lindström, Veronica and Nyman, Ulf},
  issn         = {1434-6621},
  keyword      = {chronic kidney disease,creatinine,cystatin C,glomerular filtration,rate,kidney function tests},
  language     = {eng},
  number       = {3},
  pages        = {403--414},
  publisher    = {De Gruyter},
  series       = {Clinical Chemistry and Laboratory Medicine},
  title        = {Accuracy of GFR estimating equations combining standardized cystatin C and creatinine assays: a cross-sectional study in Sweden},
  url          = {http://dx.doi.org/10.1515/cclm-2014-0578},
  volume       = {53},
  year         = {2015},
}