title: The (99m)Tc-DTPA urinary clearance method may be preferable to the plasma disappearance method for assessing glomerular filtration rate in diabetic nephropathy.
abstract: BACKGROUND
  Isotopic glomerular filtration rate (iGFR) measurement is comparable to the inulin method. In this study, we compared urinary and plasma iGFR methodologies in patients with diabetic nephropathy.
  
  
  METHODS
  A total of 147 patients from 3 sites in the Diabetic Intervention with Vitamins to Improve Nephropathy (DIVINe) trial provided 213 sets of urine and blood collections, at baseline, 18 and 36 months.
  
  
  RESULTS
  The mean (with standard deviation) plasma iGFR of 60.7 (24.9) ml/min/1.73 m(2) compared to urinary iGFR of 52.0 (28.0) ml/min/1.73 m(2) was statistically significant (p value <0.001). Although plasma and urinary iGFRs were highly related (R(2) = 0.86), plasma iGFR increasingly overestimated urinary iGFRs at lower GFRs. In contrast to the cross-sectional analyses, the two measures of iGFR were weakly related (R(2) = 0.32) in regard to patients' change over 18 months of follow-up.
  
  
  CONCLUSIONS
  Plasma iGFR may not be a suitable method for accurately measuring GFR in patients with advancing degrees of chronic kidney disease from diabetic nephropathy.
authors.affiliation: Division of Nephrology, Department of Medicine, Western University, London, Ont., Canada.
authors.forename: Shih-Han S
authors.initials: SH
authors.lastname: Huang
authors.forename: Misha
authors.initials: M
authors.lastname: Eliasziw
authors.forename: J David
authors.initials: JD
authors.lastname: Spence
authors.forename: Guido
authors.initials: G
authors.lastname: Filler
authors.forename: William C
authors.initials: WC
authors.lastname: Vezina
authors.forename: David N
authors.initials: DN
authors.lastname: Churchill
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Cattran
authors.forename: Bonnie
authors.initials: B
authors.lastname: Richardson
authors.forename: Andrew A
authors.initials: AA
authors.lastname: House
mesh_terms: D003928:Diabetic Nephropathies / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D004311:Double-Blind Method; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D011866:Radioisotope Renography / Q000379:methods*; D019275:Radiopharmaceuticals; D016284:Technetium Tc 99m Pentetate
chemical_list: D019275:Radiopharmaceuticals; D016284:Technetium Tc 99m Pentetate