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Different equations to combine creatinine and cystatin C to predict GFR. Arithmetic mean of existing equations performs as well as complex combinations

Nyman, Ulf; Grubb, Anders LU ; Sterner, Gunnar LU and Björk, Jonas LU (2009) In Scandinavian Journal of Clinical & Laboratory Investigation 69(5). p.619-627
Abstract
Purpose: To test various ways of combining creatinine and cystatin C in equations to predict glomerular filtration rate (GFR). Material and methods: Performance of the following expressions to predict GFR was compared with measured GFR (iohexol clearance, mL/min/1.73 m(2)) in 857 patients: (i) Lund-Malmo creatinine equation, (ii) Grubb cystatin C equation, (iii) arithmetic mean of (1) and (2), (iv) geometric mean of (1) and (2), (v) linear regression on (1) and (2), (vi) regression on (1) and cystatin C, and (vii) regression on creatinine, cystatin C, age and gender. Results: For the entire cohort median percent error (bias) was <5% for all expressions, though all expressions tended to underestimate (<8.3 to <15.8%) GFR at levels... (More)
Purpose: To test various ways of combining creatinine and cystatin C in equations to predict glomerular filtration rate (GFR). Material and methods: Performance of the following expressions to predict GFR was compared with measured GFR (iohexol clearance, mL/min/1.73 m(2)) in 857 patients: (i) Lund-Malmo creatinine equation, (ii) Grubb cystatin C equation, (iii) arithmetic mean of (1) and (2), (iv) geometric mean of (1) and (2), (v) linear regression on (1) and (2), (vi) regression on (1) and cystatin C, and (vii) regression on creatinine, cystatin C, age and gender. Results: For the entire cohort median percent error (bias) was <5% for all expressions, though all expressions tended to underestimate (<8.3 to <15.8%) GFR at levels <90 mL/min/1.73 m(2). The five expressions combining creatinine and cystatin C significantly improved correlation and accuracy (p < 0.001) within 15 and 30% of measured GFR compared with the equations based on the separate analytes and with no significant difference between the five expressions. In a subgroup of patients with neurological disease and muscle atrophy the cystatin C equation performed better than the expressions combining creatinine and cystatin C. Conclusion: Simply calculating the arithmetic mean of predicted GFR based on separate creatinine and cystatin C equations performs equally well as more complex equations. Reporting GFR based on separate creatinine and cystatin C equations, and their arithmetic mean also has the definite advantage that the physician can choose the estimated GFR, most appropriate depending on the clinical setting and patient characteristics. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
glomerular filtration rate, Kidney disease, kidney function tests, renal insufficiency
in
Scandinavian Journal of Clinical & Laboratory Investigation
volume
69
issue
5
pages
619 - 627
publisher
Informa Healthcare
external identifiers
  • wos:000269541400013
  • scopus:70249092880
ISSN
1502-7686
DOI
10.1080/00365510902946992
language
English
LU publication?
yes
id
477b85d2-1a72-4392-8f16-18e22a9ce2d0 (old id 1474944)
date added to LUP
2009-10-02 12:44:45
date last changed
2017-09-24 04:07:28
@article{477b85d2-1a72-4392-8f16-18e22a9ce2d0,
  abstract     = {Purpose: To test various ways of combining creatinine and cystatin C in equations to predict glomerular filtration rate (GFR). Material and methods: Performance of the following expressions to predict GFR was compared with measured GFR (iohexol clearance, mL/min/1.73 m(2)) in 857 patients: (i) Lund-Malmo creatinine equation, (ii) Grubb cystatin C equation, (iii) arithmetic mean of (1) and (2), (iv) geometric mean of (1) and (2), (v) linear regression on (1) and (2), (vi) regression on (1) and cystatin C, and (vii) regression on creatinine, cystatin C, age and gender. Results: For the entire cohort median percent error (bias) was &lt;5% for all expressions, though all expressions tended to underestimate (&lt;8.3 to &lt;15.8%) GFR at levels &lt;90 mL/min/1.73 m(2). The five expressions combining creatinine and cystatin C significantly improved correlation and accuracy (p &lt; 0.001) within 15 and 30% of measured GFR compared with the equations based on the separate analytes and with no significant difference between the five expressions. In a subgroup of patients with neurological disease and muscle atrophy the cystatin C equation performed better than the expressions combining creatinine and cystatin C. Conclusion: Simply calculating the arithmetic mean of predicted GFR based on separate creatinine and cystatin C equations performs equally well as more complex equations. Reporting GFR based on separate creatinine and cystatin C equations, and their arithmetic mean also has the definite advantage that the physician can choose the estimated GFR, most appropriate depending on the clinical setting and patient characteristics.},
  author       = {Nyman, Ulf and Grubb, Anders and Sterner, Gunnar and Björk, Jonas},
  issn         = {1502-7686},
  keyword      = {glomerular filtration rate,Kidney disease,kidney function tests,renal insufficiency},
  language     = {eng},
  number       = {5},
  pages        = {619--627},
  publisher    = {Informa Healthcare},
  series       = {Scandinavian Journal of Clinical & Laboratory Investigation},
  title        = {Different equations to combine creatinine and cystatin C to predict GFR. Arithmetic mean of existing equations performs as well as complex combinations},
  url          = {http://dx.doi.org/10.1080/00365510902946992},
  volume       = {69},
  year         = {2009},
}