title: Variability of glomerular filtration rate estimation equations in elderly Chinese patients with chronic kidney disease.
abstract: BACKGROUND
  Chronic kidney disease (CKD) is recognized worldwide as a public health problem, and its prevalence increases as the population ages. However, the applicability of formulas for estimating the glomerular filtration rate (GFR) based on serum creatinine (SC) levels in elderly Chinese patients with CKD is limited.
  
  
  METHODS
  Based on values obtained with the technetium-99m diethylenetriaminepentaacetic acid ((99m)Tc-DTPA) renal dynamic imaging method, 319 elderly Chinese patients with CKD were enrolled in this study. Serum creatinine was determined by the enzymatic method. The GFR was estimated using the Cockroft-Gault (CG) equation, the Modification of Diet in Renal Disease (MDRD) equations, the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation, the Jelliffe-1973 equation, and the Hull equation.
  
  
  RESULTS
  The median of difference ranged from -0.3-4.3 mL/min/1.73 m(2). The interquartile range (IQR) of differences ranged from 13.9-17.6 mL/min/1.73 m(2). Accuracy with a deviation less than 15% ranged from 27.6%-32.9%. Accuracy with a deviation less than 30% ranged from 53.6%-57.7%. Accuracy with a deviation less than 50% ranged from 74.9%-81.5%. None of the equations had accuracy up to the 70% level with a deviation less than 30% from the standard glomerular filtration rate (sGFR). Bland-Altman analysis demonstrated that the mean difference ranged from -3.0-2.4 mL/min/1.73 m(2). However, the agreement limits of all the equations, except the CG equation, exceeded the prior acceptable tolerances defined as 60 mL/min/1.73 m(2). When the overall performance and accuracy were compared in different stages of CKD, GFR estimated using the CG equation showed promising results.
  
  
  CONCLUSIONS
  Our study indicated that none of these equations were suitable for estimating GFR in the elderly Chinese population investigated. At present, based on overall performance, as well as performance in different CKD stages, the CG equation may be the most accurate for estimating GFR in elderly Chinese patients with CKD.
authors.affiliation: Department of Internal Medicine, The Third Affiliated Hospital of Sun Yet-sun University, Guangzhou, China.
authors.forename: Xun
authors.initials: X
authors.lastname: Liu
authors.forename: Mu-hua
authors.initials: MH
authors.lastname: Cheng
authors.forename: Cheng-gang
authors.initials: CG
authors.lastname: Shi
authors.forename: Cheng
authors.initials: C
authors.lastname: Wang
authors.forename: Cai-lian
authors.initials: CL
authors.lastname: Cheng
authors.forename: Jin-xia
authors.initials: JX
authors.lastname: Chen
authors.forename: Hua
authors.initials: H
authors.lastname: Tang
authors.forename: Zhu-jiang
authors.initials: ZJ
authors.lastname: Chen
authors.forename: Zeng-chun
authors.initials: ZC
authors.lastname: Ye
authors.forename: Tan-qi
authors.initials: TQ
authors.lastname: Lou
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002681:China; D003404:Creatinine / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007677:Kidney Function Tests; D008297:Male; D008875:Middle Aged; D051436:Renal Insufficiency, Chronic / Q000175:diagnosis / Q000453:epidemiology* / Q000378:metabolism; D015203:Reproducibility of Results; D016284:Technetium Tc 99m Pentetate
chemical_list: D003404:Creatinine; D016284:Technetium Tc 99m Pentetate
keywords: Chinese; elderly; equation; glomerular filtration rate; serum creatinine