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.
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.
Stevens
Lesley A
LA
Tufts Medical Center, Boston, MA 02111, USA. lstevens1@tuftsmedicalcenter.org
Schmid
Christopher H
CH
Greene
Tom
T
Zhang
Yaping Lucy
YL
Beck
Gerald J
GJ
Froissart
Marc
M
Hamm
Lee L
LL
Lewis
Julia B
JB
Mauer
Michael
M
Navis
Gerjan J
GJ
Steffes
Michael W
MW
Eggers
Paul W
PW
Coresh
Josef
J
Levey
Andrew S
AS
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