title: Comparative performance of the CKD Epidemiology Collaboration (CKD-EPI) and the Modification of Diet in Renal Disease (MDRD) Study equations for estimating GFR levels above 60 mL/min/1.73 m2.
abstract: BACKGROUND
  The Modification of Diet in Renal Disease (MDRD) Study equation underestimates measured glomerular filtration rate (GFR) at levels>60 mL/min/1.73 m2, with variable accuracy among subgroups; consequently, estimated GFR (eGFR)>or=60 mL/min/1.73 m2 is not reported by clinical laboratories. Here, performance of a more accurate GFR-estimating equation, the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation, is reported by level of GFR and clinical characteristics.
  
  
  METHODS
  Test of diagnostic accuracy.
  
  
  METHODS
  Pooled data set of 3,896 people from 16 studies with measured GFR (not used for the development of either equation). Subgroups were defined by eGFR, age, sex, race, diabetes, prior solid-organ transplant, and body mass index.
  
  
  METHODS
  eGFR from the CKD-EPI and MDRD Study equations and standardized serum creatinine.
  
  
  METHODS
  Measured GFR using urinary or plasma clearance of exogenous filtration markers.
  
  
  RESULTS
  Mean measured GFR was 68+/-36 (SD) mL/min/1.73 m2. For eGFR<30 mL/min/1.73 m2, both equations have similar bias (median difference compared with measured GFR). For eGFR of 30-59 mL/min/1.73 m2, bias was decreased from 4.9 to 2.1 mL/min/1.73 m2 (57% improvement). For eGFR of 60-89 mL/min/1.73 m2, bias was decreased from 11.9 to 4.2 mL/min/1.73 m2 (61% improvement). For eGFR of 90-119 mL/min/1.73 m2, bias was decreased from 10.0 to 1.9 mL/min/1.73 m2 (75% improvement). Similar or improved performance was noted for most subgroups with eGFR<90 mL/min/1.73 m2, other than body mass index<20 kg/m2, with greater variation noted for some subgroups with eGFR>or=90 mL/min/1.73 m2.
  
  
  CONCLUSIONS
  Limited number of elderly people and racial and ethnic minorities with measured GFR.
  
  
  CONCLUSIONS
  The CKD-EPI equation is more accurate than the MDRD Study equation overall and across most subgroups. In contrast to the MDRD Study equation, eGFR>or=60 mL/min/1.73 m2 can be reported using the CKD-EPI equation.
authors.affiliation: Tufts Medical Center, Boston, MA 02111, USA. lstevens1@tuftsmedicalcenter.org
authors.forename: Lesley A
authors.initials: LA
authors.lastname: Stevens
authors.forename: Christopher H
authors.initials: CH
authors.lastname: Schmid
authors.forename: Tom
authors.initials: T
authors.lastname: Greene
authors.forename: Yaping Lucy
authors.initials: YL
authors.lastname: Zhang
authors.forename: Gerald J
authors.initials: GJ
authors.lastname: Beck
authors.forename: Marc
authors.initials: M
authors.lastname: Froissart
authors.forename: Lee L
authors.initials: LL
authors.lastname: Hamm
authors.forename: Julia B
authors.initials: JB
authors.lastname: Lewis
authors.forename: Michael
authors.initials: M
authors.lastname: Mauer
authors.forename: Gerjan J
authors.initials: GJ
authors.lastname: Navis
authors.forename: Michael W
authors.initials: MW
authors.lastname: Steffes
authors.forename: Paul W
authors.initials: PW
authors.lastname: Eggers
authors.forename: Josef
authors.initials: J
authors.lastname: Coresh
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Levey
mesh_terms: D000328:Adult; D000368:Aged; D015982:Bias; D002908:Chronic Disease; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007674:Kidney Diseases / Q000503:physiopathology*; D007677:Kidney Function Tests / Q000379:methods / Q000706:statistics & numerical data; D008297:Male; D008433:Mathematics; D008875:Middle Aged; D015203:Reproducibility of Results