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Cystatin C–Based Equation to Estimate GFR without the Inclusion of Race and Sex

Pottel, Hans ; Björk, Jonas LU ; Rule, Andrew D. ; Ebert, Natalie ; Eriksen, Bjørn O. ; Dubourg, Laurence ; Vidal-Petiot, Emmanuelle ; Grubb, Anders LU orcid ; Hansson, Magnus and Lamb, Edmund J. , et al. (2023) In The New England journal of medicine 388(4). p.333-343
Abstract
BACKGROUND
The accuracy of estimation of kidney function with the use of routine metabolic tests, such as measurement of the serum creatinine level, has been controversial. The European Kidney Function Consortium (EKFC) developed a creatinine-based equation (EKFC eGFRcr) to estimate the glomerular filtration rate (GFR) with a rescaled serum creatinine level (i.e., the serum creatinine level is divided by the median serum creatinine level among healthy persons to control for variation related to differences in age, sex, or race). Whether a cystatin C–based EKFC equation would increase the accuracy of estimated GFR is unknown.
METHODS
We used data from patients in Sweden to estimate the rescaling factor for the cystatin C level... (More)
BACKGROUND
The accuracy of estimation of kidney function with the use of routine metabolic tests, such as measurement of the serum creatinine level, has been controversial. The European Kidney Function Consortium (EKFC) developed a creatinine-based equation (EKFC eGFRcr) to estimate the glomerular filtration rate (GFR) with a rescaled serum creatinine level (i.e., the serum creatinine level is divided by the median serum creatinine level among healthy persons to control for variation related to differences in age, sex, or race). Whether a cystatin C–based EKFC equation would increase the accuracy of estimated GFR is unknown.
METHODS
We used data from patients in Sweden to estimate the rescaling factor for the cystatin C level in adults. We then replaced rescaled serum creatinine in the EKFC eGFRcr equation with rescaled cystatin C, and we validated the resulting EKFC eGFRcys equation in cohorts of White patients and Black patients in Europe, the United States, and Africa, according to measured GFR, levels of serum creatinine and cystatin C, age, and sex.
RESULTS
On the basis of data from 227,643 patients in Sweden, the rescaling factor for cystatin C was estimated at 0.83 for men and women younger than 50 years of age and 0.83+0.005×(age–50) for those 50 years of age or older. The EKFC eGFRcys equation was unbiased, had accuracy that was similar to that of the EKFC eGFRcr equation in both White patients and Black patients (11,231 patients from Europe, 1093 from the United States, and 508 from Africa), and was more accurate than the Chronic Kidney Disease Epidemiology Collaboration eGFRcys equation recommended by Kidney Disease: Improving Global Outcomes. The arithmetic mean of EKFC eGFRcr and EKFC eGFRcys further improved the accuracy of estimated GFR over estimates from either biomarker equation alone.
CONCLUSIONS
The EKFC eGFRcys equation had the same mathematical form as the EKFC eGFRcr equation, but it had a scaling factor for cystatin C that did not differ according to race or sex. In cohorts from Europe, the United States, and Africa, this equation improved the accuracy of GFR assessment over that of commonly used equations. (Less)
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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
cystatin C, creatinine, GFR,
in
The New England journal of medicine
volume
388
issue
4
pages
333 - 343
publisher
Massachusetts Medical Society
external identifiers
  • scopus:85149652878
  • pmid:36720134
ISSN
0028-4793
DOI
10.1056/NEJMoa2203769
language
English
LU publication?
yes
id
689aaf61-e0d4-4b6f-948e-f10f96721f5b
date added to LUP
2023-01-29 17:58:03
date last changed
2024-05-16 08:55:50
@article{689aaf61-e0d4-4b6f-948e-f10f96721f5b,
  abstract     = {{BACKGROUND<br/>The accuracy of estimation of kidney function with the use of routine metabolic tests, such as measurement of the serum creatinine level, has been controversial. The European Kidney Function Consortium (EKFC) developed a creatinine-based equation (EKFC eGFRcr) to estimate the glomerular filtration rate (GFR) with a rescaled serum creatinine level (i.e., the serum creatinine level is divided by the median serum creatinine level among healthy persons to control for variation related to differences in age, sex, or race). Whether a cystatin C–based EKFC equation would increase the accuracy of estimated GFR is unknown.<br/>METHODS<br/>We used data from patients in Sweden to estimate the rescaling factor for the cystatin C level in adults. We then replaced rescaled serum creatinine in the EKFC eGFRcr equation with rescaled cystatin C, and we validated the resulting EKFC eGFRcys equation in cohorts of White patients and Black patients in Europe, the United States, and Africa, according to measured GFR, levels of serum creatinine and cystatin C, age, and sex.<br/>RESULTS<br/>On the basis of data from 227,643 patients in Sweden, the rescaling factor for cystatin C was estimated at 0.83 for men and women younger than 50 years of age and 0.83+0.005×(age–50) for those 50 years of age or older. The EKFC eGFRcys equation was unbiased, had accuracy that was similar to that of the EKFC eGFRcr equation in both White patients and Black patients (11,231 patients from Europe, 1093 from the United States, and 508 from Africa), and was more accurate than the Chronic Kidney Disease Epidemiology Collaboration eGFRcys equation recommended by Kidney Disease: Improving Global Outcomes. The arithmetic mean of EKFC eGFRcr and EKFC eGFRcys further improved the accuracy of estimated GFR over estimates from either biomarker equation alone.<br/>CONCLUSIONS<br/>The EKFC eGFRcys equation had the same mathematical form as the EKFC eGFRcr equation, but it had a scaling factor for cystatin C that did not differ according to race or sex. In cohorts from Europe, the United States, and Africa, this equation improved the accuracy of GFR assessment over that of commonly used equations.}},
  author       = {{Pottel, Hans and Björk, Jonas and Rule, Andrew D. and Ebert, Natalie and Eriksen, Bjørn O. and Dubourg, Laurence and Vidal-Petiot, Emmanuelle and Grubb, Anders and Hansson, Magnus and Lamb, Edmund J. and Littmann, Karin and Mariat, Christophe and Melsom, Toralf and Schaeffner, Elke and Sundin, Per-Ola and Åkesson, Anna and Larsson, Anders and Cavalier, Etienne and Bukenya, Justine and Sumaili, Ernest K. and Yayo, Eric and Monnet, Dagui and Flamant, Martin and Nyman, Ulf and Delanaye, Pierre}},
  issn         = {{0028-4793}},
  keywords     = {{cystatin C, creatinine, GFR,}},
  language     = {{eng}},
  month        = {{01}},
  number       = {{4}},
  pages        = {{333--343}},
  publisher    = {{Massachusetts Medical Society}},
  series       = {{The New England journal of medicine}},
  title        = {{Cystatin C–Based Equation to Estimate GFR without the Inclusion of Race and Sex}},
  url          = {{http://dx.doi.org/10.1056/NEJMoa2203769}},
  doi          = {{10.1056/NEJMoa2203769}},
  volume       = {{388}},
  year         = {{2023}},
}