Nephrol Dial Transplant (2023) 38: 1–6 https://doi.org/10.1093/ndt/gfac254 Advance Access publication date 7 September 2022 What should European nephrology do with the new CKD-EPI EDITORIAL equation? Ron T. Gansevoort 1 , Hans-Joachim Anders2 , Mario Cozzolino3 , Danilo Fliser4 , Denis Fouque5 , Alberto Ortiz6,7 , Maria José Soler8 and Christoph Wanner9 1 Department of Nephrology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands, 2 Renal Division, Hospital of the Ludwig Maximilans University, Munich, Germany, 3 Department of Health Sciences, University of Milan, Renal Division, ASST Santi Paolo e Carlo, Milan, Italy, 4 Department of Internal Medicine IV, Renal and Hypertensive Disease, University Medical Center, Homburg, Saar, Germany, 5 Department of Nephrology, Hospices Civils de Lyon, Centre Hospitalier Lyon-Sud, Pierre-Benite, University of Lyon, France, 6 Department of Nephrology, IIS-Fundacion Jimenez Diaz- UAM, Madrid, Spain, 7 Department of Medicine, Universidad Autonoma de Madrid, Madrid, Spain, 8 Department of Nephrology, Hospital Vall d’Hebron, Barcelona, Vall d’Hebron Research Institute (VHIR), Barcelona, Spain and 9 Department of Internal Medicine I and Comprehensive Heart Failure Center, University Hospital Würzburg, Würzburg, Germany Correspondence to: Ron T. Gansevoort; E-mail: r.t.gansevoort@umcg.nl BAC KG ROU N D because it was widely accepted [5, 6]. In 2009 it was replaced Knowledge about a patient’s glomerular filtration rate (GFR) is by the Chronic Kidney Disease Epidemiology Collaboration central to the practice of medicine. It is needed to diagnose and (CKD-EPI) equation, which was more accurate at higher GFR classify chronic kidney disease (CKD), and helpful to establish [7]. This latter equation has become the standard method for prognosis [1]. In addition, it is used to decide when to start estimating GFR across the world. specific medication, how to dose medication and when to refer patients for specialist nephrology care or when to start kidney P ROB L E M S W I T H T H E 2 0 0 9 C K D - E P I function replacement treatment. GFR can best be measured E QUAT ION (mGFR) by injection of exogenous tracers, such as iothalamate and iohexol, and serial blood sampling. This is a relatively A problem with the 2009 CKD-EPI equation is that besides cumbersome and expensive technique, and is therefore only information on age, sex and creatinine, it also requires used in specific cases. In clinical practice, equations are used to information on race. During recent years it has been argued estimate GFR (Fig. 1 and Table 1). Theseequations use readily that race is a social, political and legal rather than a biological available information about patient characteristics, such as construct, and that the incorrect use of race may have a age and sex, and about creatinine as an endogenous filtration negative effect on health equity [8]. The National Kidney marker. The oldest equation is the one developed by Cockcroft Foundation (NKF) and the American Society of Nephrology and Gault in 1976 [2]. It should be noted that their equation (ASN) announced therefore in 2021 that “race modifiers does not estimate GFR, but creatinine clearance. Creatinine should not be included in equations used to estimate kidney clearance is determined not only by glomerular filtration function” and that “current race-based equations should of creatinine, but also by tubular secretion of creatinine. be replaced by a substitute that is accurate, representative, Tubular creatinine clearance can amount to up to 50% of unbiased, and provides a standardized approach to diagnosing total creatinine clearance, especially in subjects with impaired kidney diseases” [9]. To achieve these goals the NKF and the kidney function and obesity [3]. Consequently, the Cockcroft– ASN established a task force to reassess inclusion of race in the Gault equation should not be used to estimate kidney function estimation of GFR in the USA. because it can overestimate GFR considerably. In that respect it is surprising that the summary of product characteristics for many drugs evaluated by regulatory agencies, even novel W H Y WOU L D R AC E M AT T E R W H E N drugs, still refer to the Cockcroft–Gault creatinine clearance E ST I M AT I NG G F R ? for dose adjustment [4]. The Modification of Diet in Renal Why the race coefficient was developed and scientific draw- Disease (MDRD) equation was developed in 1999 to improve backs of using it have recently been reviewed by Delanaye prediction of GFR, which was a major step forward also et al. [10]. During the development of the CKD-EPI equation it © The Author(s) 2022. Published by Oxford University Press on behalf of the ERA. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial License (https://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com The 2021 CKD–EPI estimation equation without race covariate Developers’ perspective European perspective Estimated Estimated glomerular • In Blacks underestimates • In European Blacks creatinine clearance filtration rate mGFR by 3.6 ml/min/1.73 m2, underestimates mGFR by 3.5 leading to: ml/min/1.73 m2 • 14% increase in CKD • In European Whites overestimates 1976 1999 2009 2021 prevalence vs. 2009 CKD–EPI mGFR by 6.0 ml/min/1.73 m2 Cockroft-Gault MDRD CKD–EPI CKD–EPI • In non-Blacks overestimates • eGFR increases 3.9 ml/min/1.73 m2 mGFR by 3.9 ml/min/1.73 m2 • CKD G3a–5 prevalence decreases Race-agnostic (up to 6 in subjects > 65 years), 25%, especially in ≥ 65 years, leading to: diabetes, CVD • 12% decrease in CKD • Higher CVD risk in persons prevalence vs. 2009 CKD–EPI reclassified as non-CKD than in Black Non-Black those not reclassified Overestimates mGFR Overestimates mGFR by 3.7 ml/min/1.73 m2 by 0.5 ml/min/1.73 m2 Natural comparator Danger of adopting Adopted in Europe as race-agnostic • Missing persons at high CVD risk that may benefit from interventions prescribed on the basis of CKD status Figure 1: The development over time of the various GFR estimation equations, and their strengths and weaknesses. Table 1: Oversight of the various equations to estimate kidney function. (i) The Cockcroft–Gault equation to estimate 24-h creatinine clearance (in mL/min), developed in 1976 [2]: (140 – age in years) × weight in kg/(0.81 × serum creatinine in μmol/L) (× 0.85 for women) (ii) The 4-variable MDRD equation to estimate GFR (in mL/min/1.73 m2 ), developed in 1999 [5, 6]: 175 × (serum creatinine in μmol/L)/88.4)−1.154 × age in years−0.203 (× 0.742 for women) (× 1.210 if individual is Black) (iii) The 2009 CKD-EPI equation to estimate GFR (in mL/min/1.73 m2 ), developed in 2009 with race coefficient [7]: Female and SCr ≤0.7 mg/dL: 144 × (SCr/0.7)−0.329 × 0.9929age × 1.159 (if individual is Black) Female and SCr >0.7 mg/dL: 144 × (SCr/0.7)−1.209 × 0.9929age × 1.159 (if individual is Black) Male and SCr ≤0.9 mg/dL: 141 × (SCr/0.9)−0.411 × 0.9929age × 1.159 (if individual is Black) Male and SCr >0.9 mg/dL: 141 × (SCr/0.9)−1.209 × 0.9929age × 1.159 (if individual is Black) (iv) The 2021 CKD-EPI equation to estimate GFR (in mL/min/1.73 m2 ), developed in 2021 without race coefficient [12]: Female and SCr ≤0.7 mg/dL: 143 × (SCr/0.7)−0.241 × 0.9938age in years Female and SCr >0.7 mg/dL: 143 × (SCr/0.7)−1.200 × 0.9938age in years Male and SCr ≤0.9 mg/dL: 142 × (SCr/0.9)−0.302 × 0.9938age in years Male and SCr >0.9 mg/dL: 142 × (SCr/0.9)−1.200 × 0.9938 age in years (v) The EKFC equation to estimate GFR (in mL/min/1.73 m2 ), developed in 2021 [18, 20]: 2–40 years and SCr/Q <1: 107.3 × (SCr/Q)−0.322 2–40 years and SCr/Q ≥1: 107.3 × (SCr/Q)−1.132 >40 years and SCr/Q <1: 107.3 × (SCr/Q)−0.322 × 0.990(age in years – 40) >40 years and SCr/Q ≥1: 07.3 × (SCr/Q)−1.132 × 0.990(age in years – 40) Q-values For ages 18–25 years, males: ln(Q) = 3.2 + 0.259 × age – 0.543 × ln(age) – 0.00763 × age2 + 0.000079 × age3 For ages 18–25 years, females: ln(Q) = 3.08 + 0.177 × age – 0.223 × ln(age) – 0.00596 × age2 + 0.0000686 × age3 For ages ≥25 years, Caucasian European males: Q = 0.90 mg/dL For ages ≥25 years, Caucasian European females: Q = 0.70 mg/dL For Black Africans, females: Q = Q + 0.02 For Black Africans, males: Q = Q + 0.06 For Black European, females: Q = Q + 0.04 For Black European, males: Q = Q + 0.12 SCr, serum creatinine. was observed that the relationship between mGFR and serum 1.159 to obtain an estimated GFR (eGFR) value for African- creatinine was different in Black and White participants. It was Americans. A problem, however, might be the selection of argued that these divergent results may be explained by the Black people in the study that led to the 2009 CKD-EPI difference in muscle mass between Black and White people. An equation. As Delanaye et al. argue, the great majority of Black African-American race coefficient was therefore introduced. participants came from one study, the African American Study The results for non-Blacks were to be multiplied by the factor of Kidney Disease and Hypertension (AASK) [10]. Specific 2 R.T. Gansevoort et al. methodological aspects of this study could therefore have had prevalence and risk prediction, with different results for Black a serious impact on the accuracy of the CKD-EPI equation and non-Black race groups. for Black people. For instance, the body composition with As a side note, the CKD-EPI also developed new equations respect to muscle mass of Black participants in the AASK study based on cystatin C only, and on creatinine plus cystatin may not be representative for the overall Black population in C. It was shown that the equation for cystatin C only the USA and elsewhere. Other theoretical reasons why serum did not perform better than the one for creatinine only creatinine may differ between Black and White people at a [16], and that these combined equations performed slightly same level of GFR could be differences in tubular secretion of better than equations incorporating only creatinine or only creatinine or a difference in the intake of meat as exogenous cystatin C [12, 16]. source of creatinine. It should be noted that these factors have Shortly after publication of these results, the NKF-ASN task all been poorly studied. force issued several recommendations, among which was to implement immediately for US adults the new 2021 CKD-EPI equation, which does not contain a race coefficient [17]. The DE V E L OP M E N T OF T H E 2 0 2 1 C K D - E P I slightly poorer performance of the new eGFR equation in non- E QUAT ION W I T HOU T T H E R AC E T E R M Black people was apparently felt to be a reasonable price to pay In the wake of racial reckoning since the spring of 2020 in the to avoid the questionable race coefficient. USA, efforts have led to the examination of traditional medical algorithms that incorporate race modifiers [11]. Prominent W HAT D OE S T H E JOU R NA L A DD TO T H I S among these efforts has been reconsideration of race-based DI S C U S SION ? adjustment in GFR estimation equations, and most important has been the initiative by the CKD-EPI research group. In 2021 In this issue of Nephrology Dialysis Transplantation (NDT) these investigators developed new equations that do not use two original articles are published that test the 2021 CKD- race, and compared their accuracy with that of their previous, EPI equation in European settings. The first investigated 2009 CKD-EPI equation [12]. In their validation set which how well it performs to estimate GFR in various Black included 4050 subjects, of which 579 were Black individuals, and White populations [18]. The second studied the impact the old 2009 CKD-EPI equation which uses sex, age, race and of using 2021 CKD-EPI equation on CKD prevalence and creatinine overestimated mGFR by 3.7 mL/min/1.73 m2 in prognostic accuracy [19]. Both studies are of interest for several Blacks and by 0.5 mL/min/1.73 m2 in non-Blacks. The new reasons, among which because they report on large numbers 2021 CKD-EPI equation that has no race coefficient performs of subjects, which renders these results robust. The results slightly worse on a population level because it underestimated are also described in much detail, with an abundance of mGFR by 3.6 mL/min/1.73 m2 in Blacks and overestimated supplementary material made available to the readers, which mGFR by 3.9 mL/min/1.73 m2 in non-Blacks. Thus, in Blacks allows an independent judgement. Also important is that they the absolute bias in estimating mGFR is similar with the old report on European or predominantly European populations, and new equations, albeit the 3.7 mL/min/1.73 m2 overesti- which may help guide European nephrology in deciding what mation has become a 3.6 mL/min/1.73 m2 underestimation. to do with the new CKD-EPI equation. These two studies are Although absolute bias may mathematically have remained described in the two paragraphs below. similar in Blacks, this change from over- into underestimation will be important from a healthcare perspective, because it is How well does the 2021 CKD-EPI equation estimate expected to lead to, for instance, earlier referral for start of GFR? dialysis or kidney transplantation [13, 14]. The 2020 census showed that the US population consists Delanaye et al. studied on behalf of the European Kidney of 12.4% Black and 87.6% non-Black subjects [15]. In the Function Consortium (EKFC) the accuracy of the 2009 larger population of non-Blacks, the new 2021 CKD-EPI and 2021 CKD-EPI equations, as well as the accuracy of equation is less accurate, with an overestimation of now 3.9 a GFR estimation equation that this consortium previously instead of 0.5 mL/min/1.73 m2 , whereas imprecision remained developed, the EKFC equation [18, 20]. This equation uses nearly similar (more than 10% of eGFR values are more than sex-, age- and race-specific median creatinine values obtained 30% different from mGFR) [12]. It was calculated that when from healthy subjects to mathematically estimate GFR from a adopting the 2021 CKD-EPI equation, the prevalence of CKD given serum creatinine value [20]. This study was performed among Black persons will go up from 14.3% to 16.3%. In in a relatively large population of 13 856 subjects (of which contrast, in non-Blacks it will go down from 11.7% to 10.3% 1572 were Black) in whom GFR was measured with exogenous [12]. The largest difference in accuracy in non-Blacks with the tracers. The authors found that in European Whites the new versus the old CKD-EPI equation was found in subjects accuracy of the 2021 CKD-EPI equation was lower than in >65 years old, with an overestimation of mGFR by around 6 non-Blacks in the publication by CKD-EPI. In fact, of the instead of around 1 mL/min/1.73 m2 [12]. For an individual, three equations tested, the accuracy of the 2021 CKD-EPI this bias is relatively small compared with the imprecision. equation was the lowest, with an overestimation of mGFR The CKD-EPI investigators felt therefore that the change in by 6.0 mL/min/1.73 m2 , followed by an overestimation by accuracy was not meaningful. At a population level, however, 3.0 mL/min/1.73 m2 by the 2009 CKD-EPI equation [18]. these changes in bias can lead to important differences in CKD The best performance was noted for the EKFC equation, with The new CKD-EPI equation in Europe 3 a slight underestimation of 0.3 mL/min/1.73 m2 [18]. The A RG UM E N T S FAVOR I NG A N D OP P O SI NG authors offer several explanations for why the 2021 CKD-EPI C HA NG I NG T H E C K D - E P I E QUAT ION equation performs less well in their study. First, an equation Given the presently available data, the question is now what always performs better in the cohort in which it has been European nephrology should do with the new 2021 CKD-EPI developed. This explanation can of course be used to plead equation—should it be adopted or ignored? against the CKD-EPI equation which was developed and tested There are compelling arguments to adopt it. We suggest that by CKD-EPI, as well as for the EKFC equation which was nephrology use the same language, definitions and equations developed and tested by the EKFC. Second, in the CKD-EPI across the globe. In 2019 KDIGO organized a Consensus development population the majority of studies used renal Conference to make sure that we use uniform nomenclature to clearance of iothalamate as the gold standard to measure GFR, describe kidney function and disease. This helps effective com- whereas the EKFC used various plasma clearance techniques. munication by stakeholders in the kidney health community, What the effect is of these differences in GFR measurements and is instrumental to raise public awareness of the importance techniques in the development of CKD-EPI versus EKFC of CKD [22]. We would also favor that nephrology across the equations is as yet unknown, because the so-called gold globe uses the same equations to estimate GFR. It would be standard techniques are unfortunately not well standardized awkward if a different equation were to be used in the USA nor validated against each other [21]. Third, the CKD-EPI from that used in Europe. This would impact the prevalence of equation considered non-Blacks as a whole, including Native CKD differentially. When intervention trials are designed, the American, Mexican, Asians and Hispanic people, whereas the inclusion and exclusion criteria with respect to kidney function non-Black populations in the EKFC equation was potentially may become different in the USA versus Europe. These are all more homogenous and more representative at least for the issues that should be avoided. European population. There are also convincing arguments against changing the CKD-EPI equation that is currently used in Europe. The first is that nearly all European countries do not use the race coefficient for the 2009 CKD-EPI equation. There is therefore How well does 2021 CKD-EPI eGFR predict CKD no sense of urgency to change to the official race-free 2021 complications? CKD-EPI equation. Another important reason is that the new The other original study published in this issue of NDT equation does not perform better, but worse. Because GFR is has been performed by Fu et al. [19]. These authors in- overestimated in the larger part of the population, the overall vestigated how adopting the 2021 CKD-EPI equation would CKD prevalence figures would decrease overnight. Also, the impact prevalence of CKD and risk prediction. Based on composition of the CKD population would change, since creatinine data of 1.6 million Stockholm adults with serum especially patients whom we previously thought of as high- creatinine measurements available from routine healthcare risk patients are affected, i.e. males, elderly individuals, and between 2007 and 2019 (the SCREAM cohort, Stockholm subjects with a history of diabetes or cardiovascular disease. CREAtinine Measurements), they showed that on average Would this imply that epidemiological studies that showed that eGFR would go up by a median of 3.9 (interquartile range 2.9– especially these subjects are at risk of developing CKD and 4.8) mL/min/1.73 m2 . Especially older individuals and males its complications might have to be redone? In addition, how had a larger eGFR increase. Consequently, the population should the abrupt changes in eGFR induced by adopting a prevalence of CKD G3a–5 would decrease by around 25%, new equation be explained to patients, general practitioners from 5.1% to 3.8%. Remarkably, the absolute decease in and other medical specialists? On an individual level, the CKD prevalence was highest in participants ≥65 years old, substantial reclassification to higher eGFR categories may and in those with diabetes or cardiovascular disease. This also have unwanted implications for medication initiation, is surprising, because we know from clinical practice that discontinuation and dosing, and financial coverage, and may these subgroups have a particularly high chance of progressive lead to later nephrologist referral, planning for dialysis and CKD. The clinical translation would be that fewer individuals evaluation for kidney transplantation. are perceived as having a high cardiovascular risk based on their eGFR results. In addition, individuals reclassified to a higher eGFR based on the 2021 CKD-EPI equation exhibited a higher risk of all-cause/cardiovascular death and major HOW TO M OV E F ORWA R D ? adverse cardiovascular events than those not reclassified with a Weighing the above arguments, we favor the opinion that, similar eGFR. Notwithstanding these results, the association of at the moment, European nephrology does not adopt the eGFR with kidney, cardiovascular and mortality outcomes did 2021 CKD-EPI equation to estimate GFR. When we want not differ significantly when using the 2021 CKD-EPI equation to change the existing equation, it should be a step forward. instead of the 2009 CKD-EPI equation. A limitation of this That does not seem to be the case now. Of course, we would study is that no information on race was available. This may like to align with our American colleagues, but at the same be a scientific limitation, but in clinical practice in nearly all time it should be acknowledged that the dilemma of whether countries across Europe the race coefficient is not used for the or not to adopt the 2021 CKD-EPI equation is caused by 2009 CKD-EPI equation because legally it is not permitted to American nephrology, because ASN and NKF decided to collect data on ethnicity. change without consulting their counterparts in other parts 4 R.T. Gansevoort et al. of the world. In retrospect, that should have been done in creatinine alone [16]. Moreover, the use of cystatin C alone consensus. European nephrology can therefore not be held or in combination with creatinine strengthens the association accountable for inconsistencies when it now does not align. between eGFR and the risks of death and kidney failure If European nephrology wants to make a real step forward in across diverse population [24]. Unfortunately, cystatin C is developing more accurate GFR estimation equations, there are not widely available for clinical use because not every clinical three possible solutions. First, when creatinine is maintained chemistry lab offers its measurement, and because related costs as the sole kidney function marker to be used in CKD- are in general considerably higher than for serum creatinine EPI-like GFR estimation equations, anthropometrics could be [25]. Moreover, also cystatin C is not independent of specific included as additional covariates to adjust for interindividual subjects’ characteristics. For instance, it is increased in obesity differences in muscle mass, as the most important determinant [26], hyperthyroidism [27] and inflammatory states [28], and of serum creatinine concentration besides kidney function. steroids also increase cystatin C values [29]. Furthermore, The older equations did not use weight and height as proxies standardization of cystatin C measurement has not yet been for muscle mass because at that time such information was not fully optimized [30]. Efforts should therefore be made to routinely available for many patients in clinical chemistry labs. make cystatin C available at lower costs, and to improve its Nowadays, with the widespread use of electronic patient files, standardization. At the moment measurement of cystatin C this information is stored and easy to use. But even weight for GFR estimation is especially advised for subjects with clear and height may not be sufficient as proxies for muscle mass abnormal muscle mass for their age and sex, and for subjects in an individual, as Hsu et al. pointed out recently [23]. What with an eGFR creatinine between 45 and 60 mL/min/1.73 m2 might work is when, alongside a standard GFR estimation without albuminuria, to confirm that these subjects indeed equation, additional equations are developed for subjects with have CKD. Besides cystatin C other filtration markers have disproportionally low, and for subjects with disproportionally been suggested, such as beta-2 microglobulin and beta-trace high muscle mass for their age and sex. protein [31], but as yet these analytes have been too poorly Second, the type of equation could be changed. The studied to be considered. equation that was developed by the EKFC works, and is Whichever way forward is chosen to improve GFR estima- an example of a fundamentally different approach. It uses tion, we think that we should only change to a novel equation so-called Q values, which are sex- and age-specific median when it has considerably better performance. We should creatinine values in healthy subjects, to estimate GFR for not be distracted by minor advancements because changing an individual. These Q values can be obtained for different our standard equations will inherently cause discussion and populations (instead of different races) according to age and confusion, and holds the danger that we lose credibility with gender, for instance from large local hospital databases. The other specialties that base some of their treatment decisions on validation results by the EKFC are promising. Performance in eGFR values. When a change is considered, we should try to terms of bias and accuracy seems better [18, 20], but external reach global consensus before implementing such a new GFR validation is needed, preferably by independent research estimation equation. When international nephrology uses the groups using large datasets including populations from outside same or at least a similar equation around the world, this will Europe. An advantage could also be that this equation can be have many advantages for healthcare on an individual patient used for all age groups, and not only for adults, as holds for and on a population level, as well as for science. the CKD-EPI equation (Table 1). A disadvantage could be that the eGFR results are dependent on the normal Q values that are used for various populations, because the selection of these C ONC LU SION normal values may have an arbitrary component. In addition, To avoid the incorrect use of race as a biological construct the EKFC equation has a standard Q value for Caucasian and the resulting negative effect on health equity, the novel European males and females, and adjusts these Q values for 2021 CKD-EPI equation was designed not to include a race other populations including Black individuals (Table 1). This coefficient. At present European nephrology in general uses is reminiscent of using the race conversion factor in the 2009 the 2009 CKD-EPI equation to estimate kidney function for CKD-EPI equation, the issue which started the discussion all subjects, without the Black race coefficient that this equation about the need to replace this equation. The Q values for the originally offered. From an ethical point of view changing from EKFC equation may therefore better be based on biological the 2009 to the 2021 CKD-EPI equation is therefore not felt characteristics and not have an implicit reference population. to be an improvement. Since the 2021 CKD-EPI equation also Third, we could change the analyte from creatinine, or add seems to estimate GFR less accurately than the 2009 CKD- an analyte to creatinine as marker for kidney function. In this EPI equation, by overestimating GFR in the larger part of the respect cystatin C has received most attention. In contrast to European population, there is no strong evidence to adopt creatinine, cystatin C is produced by all nucleated cells, and the new equation. European nephrology would do better to not only by myocytes. Its serum concentration is therefore await novel developments to improve GFR estimation, such as not dependent on muscle mass. The CKD-EPI research group adding anthropometrics to estimation equations, fundamen- showed that new eGFR equations that incorporate creatinine tally changing these GFR equations or using/adding analytes and cystatin C, but omit race, are more accurate and led other than creatinine as alternative filtration markers. When a to smaller differences between Black participants and non- significant improvement in accuracy and bias is achieved and Black participants than new equations without race with validated independently, efforts should be made to reach global The new CKD-EPI equation in Europe 5 consensus before novel equations are implemented to replace 13. Martins PN, Pavlakis M, Diez A. New equations for estimating the GFR the current ones. without race. N Engl J Med 2022;386:1670. 14. Worthen G, Vinson A, Tennankore K. New equations for estimating the GFR without race. N Engl J Med 2022;386:1670–1. 15. UC Census Bureau releases 2020 census. 2021. 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