title: Regressing an optimal variable to scale glomerular filtration rate: more variations in glomerular filtration rate are explained.
abstract: BACKGROUND
  To compare glomerular filtration rate (GFR) among individuals, GFR is usually scaled to body surface area (BSA) based on the ratio method, which has been debated for its accuracy in recent years. Reference to the BSA as a normalization standard is the most common method currently in use but has limitations. This study was designed to a better variable to scale GFR.
  
  
  METHODS
  We measured 99mTc- diethylene triamine pentaacetic acid plasma clearance (uncorrected GFR, uGFR) for 322 healthy adults who were enrolled according to the SENIEUR protocol. The individuals were randomly grouped into A and B for regressing and validating the optimal variable, respectively. Nonlinear regression was performed against uGFR, and the selected independent variables were body weight, height, age, and sex.
  
  
  RESULTS
  Among several tested models, the regression coefficients of weight-age formula (W-A) were in narrower 95% confidence interval (CI). The coefficient of determination of the regression line between W-A and uGFR, as an indicator to explain the percentage of variations of GFR, was higher than that of other variables in both groups. The coefficient of determination of the regression line between W-A and uGFR was 0.571, which was higher than that of BSA (0.203) or TBW (0.241).
  
  
  CONCLUSIONS
  The index variable, based on both body weight and age, has a better statistical relationship to uGFR and is a better variable to scale GFR in adults.
authors: From the *Department of Nuclear Medicine, the First Affiliated Hospital of Anhui Medical University, Hefei, Anhui Province, People's Republic of China; †Department of Nuclear Medicine, Chinese PLA General Hospital, Beijing, People's Republic of China; and ‡Department of Nephrology, Chinese PLA General Hospital, Beijing, People's Republic of China.
authors: Si
authors: S
authors: Hongwei
authors: Chen
authors: C
authors: Yingmao
authors: Shao
authors: S
authors: Mingzhe
authors: Ma
authors: M
authors: Guangyu
authors: Xu
authors: X
authors: Baixuan
authors: Tian
authors: T
authors: Jiahe
authors: Chen
authors: C
authors: Yunshuang
authors: Sun
authors: S
authors: Xuefeng
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001830:Body Surface Area; D001835:Body Weight; D003627:Data Interpretation, Statistical; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D015203:Reproducibility of Results; D012737:Sex Factors; D016284:Technetium Tc 99m Pentetate / Q000031:analogs & derivatives* / Q000493:pharmacokinetics
chemical_list: C481867:technetium Tc 99m diethylene triamine pentaacetic acid, dimethyl ester; D016284:Technetium Tc 99m Pentetate