TY - JOUR
T1 - Estimating GFR among participants in the Chronic Renal Insufficiency Cohort (CRIC) Study
AU - Anderson, Amanda Hyre
AU - Yang, Wei
AU - Hsu, Chi Yuan
AU - Joffe, Marshall M.
AU - Leonard, Mary B.
AU - Xie, Dawei
AU - Chen, Jing
AU - Greene, Tom
AU - Jaar, Bernard G.
AU - Kao, Patricia
AU - Kusek, John W.
AU - Landis, J. Richard
AU - Lash, James P.
AU - Townsend, Raymond R.
AU - Weir, Matthew R.
AU - Feldman, Harold I.
N1 - Funding Information:
Support: In addition to funding under a cooperative agreement from NIDDK ( 5U01DK060990 , 5U01DK060984 , 5U01DK061022 , 5U01DK061021 , 5U01DK061028 , 5U01DK060980 , 5U01DK060963 , and 5U01DK060902 ), this work was supported in part by the following institutional Clinical Translational Science Awards (CTSA) and other National Institutes of Health grants: University of Pennsylvania UL1 RR-024134 , K01DK092353 , L30 DK084815 and K24DK002651 ; Johns Hopkins University UL1 RR-025005 ; University of Maryland General Clinical Research Center (GCRC) M01 RR-16500 ; Case Western Reserve University Clinical and Translational Science Collaborative (University Hospitals of Cleveland, Cleveland Clinic Foundation, and MetroHealth) UL1 RR-024989 ; University of Michigan GCRC M01 RR-000042 and CTSA UL1 RR-024986 ; University of Illinois at Chicago Clinical Research Center UL1 RR-029879 and M01 RR-013987-06 ; Tulane/LSU/Charity Hospital GCRC M01 RR-05096 ; and Kaiser NIH/NCRR UCSF-CTSI UL1 RR-024131 .
PY - 2012/8
Y1 - 2012/8
N2 - Background: Glomerular filtration rate (GFR) is considered the best measure of kidney function, but repeated assessment is not feasible in most research studies. Study Design: Cross-sectional study of 1,433 participants in the Chronic Renal Insufficiency Cohort (CRIC) Study (ie, the GFR subcohort) to derive an internal GFR estimating equation using a split-sample approach. Setting & Participants: Adults from 7 US metropolitan areas with mild to moderate chronic kidney disease; 48% had diabetes and 37% were black. Index Test: CRIC GFR estimating equation. Reference Test or Outcome: Urinary 125I-iothalamate clearance testing (measured GFR [mGFR]). Other Measurements: Laboratory measures, including serum creatinine and cystatin C, and anthropometrics. Results: In the validation data set, the model that included serum creatinine level, serum cystatin C level, age, sex, and race was the most parsimonious and similarly predictive of mGFR compared with a model additionally including bioelectrical impedance analysis phase angle, CRIC clinical center, and 24-hour urinary creatinine excretion. Specifically, root mean square errors for the separate models were 0.207 versus 0.202, respectively. Performance of the CRIC GFR estimating equation was most accurate for the subgroups of younger participants, men, nonblacks, non-Hispanics, those without diabetes, those with body mass index <30 kg/m 2, those with higher 24-hour urine creatinine excretion, those with lower high-sensitivity C-reactive protein levels, and those with higher mGFRs. Limitations: Urinary clearance of 125I-iothalamate is an imperfect measure of true GFR; cystatin C level is not standardized to certified reference material; lack of external validation; small sample sizes limit analyses of subgroup-specific predictors. Conclusions: The CRIC GFR estimating equation predicts mGFR accurately in the CRIC cohort using serum creatinine and cystatin C levels, age, sex, and race. Its performance was best in younger and healthier participants.
AB - Background: Glomerular filtration rate (GFR) is considered the best measure of kidney function, but repeated assessment is not feasible in most research studies. Study Design: Cross-sectional study of 1,433 participants in the Chronic Renal Insufficiency Cohort (CRIC) Study (ie, the GFR subcohort) to derive an internal GFR estimating equation using a split-sample approach. Setting & Participants: Adults from 7 US metropolitan areas with mild to moderate chronic kidney disease; 48% had diabetes and 37% were black. Index Test: CRIC GFR estimating equation. Reference Test or Outcome: Urinary 125I-iothalamate clearance testing (measured GFR [mGFR]). Other Measurements: Laboratory measures, including serum creatinine and cystatin C, and anthropometrics. Results: In the validation data set, the model that included serum creatinine level, serum cystatin C level, age, sex, and race was the most parsimonious and similarly predictive of mGFR compared with a model additionally including bioelectrical impedance analysis phase angle, CRIC clinical center, and 24-hour urinary creatinine excretion. Specifically, root mean square errors for the separate models were 0.207 versus 0.202, respectively. Performance of the CRIC GFR estimating equation was most accurate for the subgroups of younger participants, men, nonblacks, non-Hispanics, those without diabetes, those with body mass index <30 kg/m 2, those with higher 24-hour urine creatinine excretion, those with lower high-sensitivity C-reactive protein levels, and those with higher mGFRs. Limitations: Urinary clearance of 125I-iothalamate is an imperfect measure of true GFR; cystatin C level is not standardized to certified reference material; lack of external validation; small sample sizes limit analyses of subgroup-specific predictors. Conclusions: The CRIC GFR estimating equation predicts mGFR accurately in the CRIC cohort using serum creatinine and cystatin C levels, age, sex, and race. Its performance was best in younger and healthier participants.
KW - GFR estimation
KW - Glomerular filtration rate (GFR)
KW - kidney function
UR - http://www.scopus.com/inward/record.url?scp=84863983673&partnerID=8YFLogxK
U2 - 10.1053/j.ajkd.2012.04.012
DO - 10.1053/j.ajkd.2012.04.012
M3 - Article
C2 - 22658574
AN - SCOPUS:84863983673
SN - 0272-6386
VL - 60
SP - 250
EP - 261
JO - American Journal of Kidney Diseases
JF - American Journal of Kidney Diseases
IS - 2
ER -