title: Glomerular filtration rate-estimating equations for patients with advanced chronic kidney disease.
abstract: BACKGROUND
  Renal function is often estimated using one of several glomerular filtration rate (GFR) estimating equations. However, there is no consensus which estimating equation performs best in patients with advanced renal failure.
  
  
  METHODS
  We compared the performance of five different estimated GFR (eGFR) equations [Cockcroft-Gault, Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease (CKD) Epidemiology collaboration (CKD-EPI) and Mayo Clinic and Lund-Malmö] with measured GFR (plasma iohexol clearance) in 2098 referred CKD patients with mGFR <30 mL/min/1.73 m(2).
  
  
  RESULTS
  There were 398 patients with an mGFR ≤ 10 mL/min/1.73 m(2), 1974 with a measured GFR (mGFR) 11-20 mL/min/1.73 m(2) and 749 patients with mGFR 21-30 mL/min/1.73 m(2). Across the entire range, the median bias of eGFR was lowest for the Lund-Malmö equation (0.7 mL/min/1.73 m(2)), followed by the CKD-EPI (1.2 mL/min/1.73 m(2)), the MDRD (1.6 mL/min/1.73 m(2)), Mayo Clinic equation (1.7 mL/min/1.73 m(2)) and Cockcroft-Gault equation (4.6 mL/min/1.73 m(2)). The best accuracy within 30% of mGFR was also for Lund-Malmö (76%), while it was similar for CKD-EPI, MDRD and Mayo (65-67%). The Cockcroft-Gault had the worst accuracy of only ∼54%.The median bias was stable across mGFR categories, while the accuracy within 30% of mGFR became worse with decreasing mGFR. All equations performed best among patients with hereditary kidney diseases and tubulointerstitial disease. Accuracy was generally worse for patients >65 years of age and for those with diabetic nephropathy.
  
  
  CONCLUSIONS
  In patients with advanced renal failure, the GFR-estimating equations show reasonably good performance on the population level. On the individual patient level, they are inaccurate, especially in elderly patients and those with diabetic nephropathy.
authors.affiliation: Department of Clinical Sciences Intervention and Technology, Karolinska Institutet and Karolinska University Hospital Huddinge, Stockholm, Sweden.
authors.forename: Marie
authors.initials: M
authors.lastname: Evans
authors.forename: Karlijn J
authors.initials: KJ
authors.lastname: van Stralen
authors.forename: Staffan
authors.initials: S
authors.lastname: Schön
authors.forename: Karl-Göran
authors.initials: KG
authors.lastname: Prütz
authors.forename: Maria
authors.initials: M
authors.lastname: Stendahl
authors.forename: Bengt
authors.initials: B
authors.lastname: Rippe
authors.forename: Kitty J
authors.initials: KJ
authors.lastname: Jager
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003627:Data Interpretation, Statistical; D005260:Female; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate; D006801:Humans; D007676:Kidney Failure, Chronic / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D055815:Young Adult
keywords: CKD-EPI; Lund-Malmö; MDRD; accuracy; chronic kidney disease