No Race-Ethnicity Adjustment in CKD-EPI Equations Is Required for Estimating Glomerular Filtration Rate in the Brazilian Population

Abstract

Background . Glomerular filtration rate (GFR) is usually estimated from equations using serum creatinine (sCr), with adjustment for gender, age, and race (black or nonblack). The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) is the preferred equation for adults, but it was validated for the United States population. We intended to evaluate if the race-ethnicity adjustment proposed for the sCr-based CKD-EPI equations is appropriate for the Brazilian population. Methods . CKD outpatients had blood samples collected for determination of sCr and serum cystatin C (sCys) levels. GFR was measured (mGFR) by plasma clearance of 51 Cr-EDTA and used as the reference. We compared values of mGFR and estimated GFR (eGFR) by CKD-EPI equations based on sCr (eGFR Cr ) and on the combination of sCr and sCys (eGFR Cr-Cys ). For African Brazilian patients, eGFR was calculated either without or with race adjustment. Accuracy was considered acceptable if the difference between the values of eGFR and mGFR was ≤30% (P30). Results . 100 patients were enrolled (58 ± 14 years, 46% male, 39% white and 61% African Brazilian). Mean mGFR was 46.7 ± 29.2 ml/min/1.73 m 2 . Mean eGFR Cr and eGFR Cr-Cys without race adjustment were 47.8 ± 30.1 ml/min/1.73 m 2 and 46.4 ± 30.3 ml/min/1.73 m 2 , respectively. The corresponding P30 accuracy values were 79.0% and 83.0%. In the African Brazilian subgroup, values for mean mGFR and eGFR Cr either without or with race adjustment were 49.8 ± 32.2 ml/min/1.73 m 2 , 50.4 ± 32.7 ml/min/1.73 m 2 , and 58.4 ± 37.9 ml/min/1.73 m 2 (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mi>P</mml:mi><mml:mo>&lt;</mml:mo><mml:mn>0.001</mml:mn></mml:math> vs. mGFR), respectively. P30 accuracy values for eGFR Cr either without or with race adjustment were 75.4% and 67.2%, respectively. Conclusions . The use of CKD-EPI equations without race-ethnicity adjustment seems more appropriate for the Brazilian population.

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