Estimated glomerular filtration rate equations in people of self-reported black ethnicity in the United Kingdom: Inappropriate adjustment for ethnicity may lead to reduced access to care

Abstract

Assessment in African populations suggest adjustment for ethnicity in estimated glomerular filtration rate (eGFR) equations derived from African Americans lead to overestimation of GFR and failure to determine severity in chronic kidney disease (CKD). However, studies in African Europeans are limited. We aimed to assess accuracy of eGFR equations, with and without ethnicity adjustment compared with measured GFR in people of Black ethnicity in the United Kingdom. Performance of MDRD, CKD-EPI (with and without ethnicity adjustment), Full Age Spectrum (FAS), revised Lund Malmö (LM Revised), and European Kidney Function Consortium (EKFC) eGFR equations were assessed compared to 51Cr-EDTA GFR studies extracted from hospital databases. Participants with albumin <30g/l, liver disease, <18 years, of non-Black or non-White self-reported ethnicity were excluded. Agreement was assessed by bias, precision and 30%-accuracy and was stratified for ethnicity and GFR. 1888 51Cr-EDTA studies were included (Mean age-53.7yrs; 43.6% female; 14.1% Black ethnicity). Compared to White participants, eGFR-MDRD and eGFR-CKD-EPI equations in Black participants significantly overestimated GFR (bias 20.3 and 19.7 ml/min/1.73m2 respectively, p<0.001). Disregarding the ethnicity adjustment significantly improved GFR estimates for Black participants (bias 6.7 and 2.4ml/min/1.73m2 for eGFR-MDRD and eGFR-CKD-EPI respectively, p<0.001). The LM Revised equation had the smallest bias for both White and Black participants (5.8ml and -1.1ml/min/1.73m2 respectively). 30%-accuracy was superior for GFR≥60ml/min/1.73m2 compared to <60ml/min/1.73m2 using eGFR-CKD-EPI equation for both White and Black participants (p<0.001). Multivariate regression methodology with adjustment for age, sex and log(serum creatinine) in the cohort yielded an ethnicity coefficient of 1.018 (95% CI: 1.009–1.027). Overestimation of measured GFR with eGFR equations using ethnicity adjustment factors may lead to reduced CKD diagnosis and under-recognition of severity in people of Black ethnicity. Our findings suggest that ethnicity adjustment for GFR estimation in non-African Americans may not be appropriate for use in people of Black ethnicity in the UK.

European Kidney Function Consortium Equation vs. Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) Refit Equations for Estimating Glomerular Filtration Rate: Comparison with CKD-EPI Equations in the Korean Population

“…Fourth, we excluded individuals younger than 20 yrs, and this exclusion criterion was not enough to explore the known benefit of the EKFC equation, which is applicable to the full age spectrum. However, the present study enrolled the largest number of individuals in their 20s (approximately 8000 individuals) compared with previous studies on the EKFC equation [ 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. In addition, we firstly compared the EKFC equation with sCysC-based CKD-EPI and CKD-EPI-R equations in more than 12,000 individuals.…”

“…In 2020, the European Kidney Function Consortium (EKFC) announced a new full-age spectrum eGFR equation that can be used across the entire age range. The EKFC equation was developed and validated using European and US cohorts [ 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ]; in the Asian populations, it was evaluated only in a few studies [ 16 , 17 ].…”

Modeling Chronic Kidney Disease in Type 2 Diabetes Mellitus: A Systematic Literature Review of Models, Data Sources, and Derivation Cohorts

“…Minorities were found to be at higher risk of diabetes-related mortality and adverse clinical events, including ESKD, relative to White people in multinational [149] and national studies [150,151]. Race and ethnicity may also influence whether appropriate care is received for kidney disease; in the UK, for example, adjustment for ethnicity was found to overestimate GFR in self-reported Black participants, thereby potentially delaying the time to treatment initiation [152]. Although note that, in the USA, a National Kidney Foundation and American Society for Nephrology Task Force recently recommended that creatinine equations be refit without a variable for race and that research into GFR estimation aims to eliminate race and ethnic disparities [153].…”

Applicability of 14 Formulas for Estimating Glomerular Filtration Rate in the Evaluation of Renal Function before and after Nephron‐Sparing Surgery in Patients with Renal Tumors

“…In our study, the calculation results of the four MDRD correlation formulas have no significant correlation with rGFR, indicating that they are not suitable for eGFR calculations for postoperative patients. The National Kidney Foundation (NKF) and the American Society of Nephrology (ASN) established a joint working group in 2020 to evaluate the eGFR estimation formula [ 26 ]. On November 4, 2021, NEJM officially published the results of two research teams on eGFR estimation of race coefficient.…”

“…The results of these two studies show that the eGFR estimation formula based on serum cystatin C is more accurate than the estimation formula based on serum creatinine [ 27 ]. So, they recommended the following: the race coefficient has limited influence on the eGFR calculation, and the race coefficient can be removed; each clinical laboratory should try its best to detect serum cystatin C; and further research to find better markers for eGFR estimation [ 26 , 27 ]. The population included in the MDRD study is mainly concentrated in patients aged 18–70 [ 15 ].…”