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Extending the cystatin C based EKFC-equation to children – validation results from Europe

Pottel, Hans ; Nyman, Ulf LU ; Björk, Jonas LU ; Berg, Ulla ; Bökenkamp, Arend ; Dubourg, Laurence Derain ; Lemoine, Sandrine ; Goffin, Karolien ; Grubb, Anders LU orcid and Hansson, Magnus , et al. (2023) In Pediatric Nephrology
Abstract

Background: A new cystatin C based European Kidney Function Consortium (EKFCCysC) equation was recently developed for adults, using the same mathematical form as the previously published full age spectrum creatinine based EKFC-equation (EKFCCrea). In the present study the cystatin C based EKFC-equation is extended to children, by defining the appropriate cystatin C rescaling factor QCysC. Methods: Rescaling factor QCysC for cystatin C was defined as: a) 0.83 mg/L, exactly as it was defined for young adults in the adult equation, and b) a more complex QCysC-age relationship based on 4th degree cystatin C-age polynomials after evaluation of data from Uppsala, Stockholm and... (More)

Background: A new cystatin C based European Kidney Function Consortium (EKFCCysC) equation was recently developed for adults, using the same mathematical form as the previously published full age spectrum creatinine based EKFC-equation (EKFCCrea). In the present study the cystatin C based EKFC-equation is extended to children, by defining the appropriate cystatin C rescaling factor QCysC. Methods: Rescaling factor QCysC for cystatin C was defined as: a) 0.83 mg/L, exactly as it was defined for young adults in the adult equation, and b) a more complex QCysC-age relationship based on 4th degree cystatin C-age polynomials after evaluation of data from Uppsala, Stockholm and Canada and aggregated data from Germany. The EKFCCysC equation was then validated in an independent dataset in European children (n = 2,293) with measured GFR, creatinine, cystatin C, age, height and sex available. Results: The EKFCCysC with the simple QCysC-value of 0.83 had a bias of –7.6 [95%CI –8.4;–6.5] mL/min/1.73 m2 and a P30-value of 85.8% [95%CI 84.4;87.3] equal to the EKFCCysC with the more complex 4th degree QCysC-value. The arithmetic mean of the EKFCCrea and EKFCCysC with the simple QCysC of 0.83 had a bias of –4.0 [95%CI –4.5;–3.1] mL/min/1.73 m2 and P30 of 90.4% [95%CI 89.2;91.6] similar to using the more complex 4th degree QCysC-polynomial. Conclusion: Using exactly the same QCysC of 0.83 mg/L, the adult EKFCCysC can easily be extended to children, with some bias but acceptable P30-values. The arithmetic mean of EKFCCrea and EKFCCysC results in bias closer to zero and P30 slightly over 90%. Graphical Abstract: [Figure not available: see fulltext.].

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organization
publishing date
type
Contribution to journal
publication status
in press
subject
keywords
Creatinine, Cystatin C, Estimating GFR, Full age range equation
in
Pediatric Nephrology
publisher
Springer
external identifiers
  • pmid:37875730
  • scopus:85174638454
ISSN
0931-041X
DOI
10.1007/s00467-023-06192-6
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2023, The Author(s), under exclusive licence to International Pediatric Nephrology Association.
id
7aab9672-3fbf-4f41-92f2-a0d08fde13ae
date added to LUP
2023-12-13 15:27:28
date last changed
2024-04-12 07:17:12
@article{7aab9672-3fbf-4f41-92f2-a0d08fde13ae,
  abstract     = {{<p>Background: A new cystatin C based European Kidney Function Consortium (EKFC<sub>CysC</sub>) equation was recently developed for adults, using the same mathematical form as the previously published full age spectrum creatinine based EKFC-equation (EKFC<sub>Crea</sub>). In the present study the cystatin C based EKFC-equation is extended to children, by defining the appropriate cystatin C rescaling factor Q<sub>CysC</sub>. Methods: Rescaling factor Q<sub>CysC</sub> for cystatin C was defined as: a) 0.83 mg/L, exactly as it was defined for young adults in the adult equation, and b) a more complex Q<sub>CysC</sub>-age relationship based on 4<sup>th</sup> degree cystatin C-age polynomials after evaluation of data from Uppsala, Stockholm and Canada and aggregated data from Germany. The EKFC<sub>CysC</sub> equation was then validated in an independent dataset in European children (n = 2,293) with measured GFR, creatinine, cystatin C, age, height and sex available. Results: The EKFC<sub>CysC</sub> with the simple Q<sub>CysC</sub>-value of 0.83 had a bias of –7.6 [95%CI –8.4;–6.5] mL/min/1.73 m<sup>2</sup> and a P30-value of 85.8% [95%CI 84.4;87.3] equal to the EKFC<sub>CysC</sub> with the more complex 4<sup>th</sup> degree Q<sub>CysC</sub>-value. The arithmetic mean of the EKFC<sub>Crea</sub> and EKFC<sub>CysC</sub> with the simple Q<sub>CysC</sub> of 0.83 had a bias of –4.0 [95%CI –4.5;–3.1] mL/min/1.73 m<sup>2</sup> and P30 of 90.4% [95%CI 89.2;91.6] similar to using the more complex 4<sup>th</sup> degree Q<sub>CysC</sub>-polynomial. Conclusion: Using exactly the same Q<sub>CysC</sub> of 0.83 mg/L, the adult EKFC<sub>CysC</sub> can easily be extended to children, with some bias but acceptable P30-values. The arithmetic mean of EKFC<sub>Crea</sub> and EKFC<sub>CysC</sub> results in bias closer to zero and P30 slightly over 90%. Graphical Abstract: [Figure not available: see fulltext.].</p>}},
  author       = {{Pottel, Hans and Nyman, Ulf and Björk, Jonas and Berg, Ulla and Bökenkamp, Arend and Dubourg, Laurence Derain and Lemoine, Sandrine and Goffin, Karolien and Grubb, Anders and Hansson, Magnus and Larsson, Anders and Littmann, Karin and Åsling-Monemi, Kajsa and Adeli, Khosrow and Cavalier, Etienne and Delanaye, Pierre}},
  issn         = {{0931-041X}},
  keywords     = {{Creatinine; Cystatin C; Estimating GFR; Full age range equation}},
  language     = {{eng}},
  publisher    = {{Springer}},
  series       = {{Pediatric Nephrology}},
  title        = {{Extending the cystatin C based EKFC-equation to children – validation results from Europe}},
  url          = {{http://dx.doi.org/10.1007/s00467-023-06192-6}},
  doi          = {{10.1007/s00467-023-06192-6}},
  year         = {{2023}},
}