Did you receive your renal panel lab results and see two eGFR results? Ever wonder why there was a separate result for African Americans?
Glomerular filtration rate (GFR) is the best way to measure how well your kidneys are working, but this test is complicated and cannot be easily done in a doctor’s office. To get around this, laboratories use mathematical equations to estimate the glomerular filtration rate instead of measuring it. This is why laboratories report estimated GFR or eGFR.
Your eGFR informs healthcare professionals about your kidney function and helps them to recommend the best treatments for you. For instance, eGFR results are used in the following ways:
● Confirming that kidney function is normal for a potential living kidney donor
● Making sure the right dose of medicine is used
● Enrollment in clinical trials that use kidney function as an inclusion or exclusion criterion
● Making sure the right type of imaging tests and dyes are used
● When to refer someone to a nephrologist or kidney doctor
● If and when to plan for dialysis
● When to start an evaluation for a kidney transplant
Using math equations, eGFR is calculated from the amount of creatinine in the blood. Creatinine is a waste product that comes from the normal wear and tear on your body’s muscles and also from the foods you eat. Everyone has creatinine in their bloodstream. However, creatinine levels can differ between people. This reason for this difference may not only be related to kidney disease – it may be affected by several other factors, such as age, sex, and body weight.
Why is race included in the eGFR calculations?
Race was originally included in eGFR calculations because clinical trials demonstrated that people who self-identify as Black or African Americans can have, on average, higher levels of creatinine in their blood. It was thought the reason was due to differences in muscle mass, diet, and the way the kidneys eliminate creatinine. Since a patient’s race is not always used when laboratory tests are ordered, laboratories used different eGFR calculations for African Americans and non-African Americans and included both numbers in their lab results.
In an article entitled, Race and eGFR: Addressing Health Disparities in Chronic Kidney Disease, it was announced that UNOS they would begin calculating eGFR without a parameter for race.
The US Renal Data System’s 2018 Annual Report showed African American patients in older age groups experienced higher rates of CKD compared to White Americans of similar age, which is consistent with many other reports. What is troubling is that not only do Black patients have a marked increased risk for end-stage renal compared to Whites, but Black patients exhibit a lower rate of kidney transplants compared to persons of other races. This is the context in which they reevaluated its measure of kidney function.
Why this race parameter is so important
Several studies suggest that the equations used to calculate eGFR may overestimate GFR in African Americans, potentially leading to underdiagnosis of CKD and delayed diagnosis of end-stage renal disease and qualifying for a transplant. All data and several studies show that African American patients have a higher prevalence of risk factors for CKD, such as hypertension, diabetes, and abnormal adjunct laboratory markers for renal disease, yet have a lower prevalence of CKD (eGFR < 60 mL/min) in this same population the way it is currently calculated. That doesn’t quite add up.
Although in clinical nephrology eGFR is not used in isolation to diagnose CKD, the potential outcomes of imprecision in eGFR in African American persons, include:
1. the way that drugs are administered or withheld based on eGFR;
2. how quickly patients are referred to nephrology for the management of CKD;
3. clinical trial eligibility; and
4. access to renal transplant waitlists.
Do you see how this causes disparities in CKD and ESRD diagnosis and treatment and transplant eligibility?
In fact, in a 2021 observational study about racial disparities in eligibility for preemptive waitlisting for kidney transplantation (Ku, et. al.), results showed that using eGFR, African Americans had 35% shorter potential wait time compared with Whites. They also estimated that registering African Americans on the waitlist as early as an eGFR of 24-25 versus the standard eGFR of 20 might improve racial equity in accruable wait time before ESRD onset. They concluded that policies allowing for waitlist registration at higher GFR levels for Black patients compared with White patients could theoretically attenuate disparities in accruable wait time and improve racial equity in transplant access.
Personally, without this race coefficient, I would have been qualified to be on the kidney transplant list almost three years earlier than I was able to register in 2019. Additionally, I would have been eligible for dialysis in 2018. I started in December 2021.
What is being done to address this disparity?
The National Kidney Foundation (NKF) and the American Society of Nephrology (ASN) formed a joint task force to review the use of race in eGFR calculations. On September 23, 2021, the Task Force announced a new race-free calculation for estimating eGFR. The National Kidney Foundation is working with the nation’s laboratories to get this new calculation into use as quickly as possible. The NKF is also creating materials to show how this new equation may impact patient care. They shared:
“Although the NKF alone cannot solve all inequalities, the NKF is working to help identify, confront and reverse them. NKF advocates for making affordable healthcare more available and making sure that communities of color are not left behind…NKF’s educational offerings include the impact of kidney disease on diverse communities, and the reasons why communities of color have been disproportionately affected by COVID-19. NKF is committed to continuing its work to address inequalities in kidney health.”
It is widely known that there are health disparities in the prevention and treatment of kidney disease in communities of people of color. So it is even more frightening that even if an African American is appropriately going to the doctor and following all doctors' orders, there is a disparity in the timing at which African Americans can receive life-saving dialysis and qualify for a life-giving kidney transplant. Any delay in diagnosis and treatment exasperates the statistic that there are more Black people who have kidney failure and die waiting for a transplant.
Policy Changes
As of July 27, 2022, the United Network for Organ Sharing (UNOS), the US transplant system, changed its policy requiring transplant hospitals to use only race-neutral eGFR formulas for data entered into UNet. To see this important policy change, click here >>> https://unos.org/news/implementation-notice-race-neutral-egfr-formulas/
Additionally, as of January 23, 2023, UNOS issued an implementation notice for waiting time modifications for candidates affected by race-inclusive eGFR calculations. It requires all transplant programs to assess their waiting lists and submit waiting time modifications for Black candidates affected by race-inclusive eGFR calculations. Find this official implementation notice here >>>> https://unos.org/news/implementation-kidney-waiting-time-mods-equity/
If you are African American, please call your nephrologist or your transplant center if you have not been contacted.
Sources:
Ku E, McCulloch CE, Adey DB, Li L, Johansen KL. Racial Disparities in Eligibility for Preemptive Waitlisting for Kidney Transplantation and Modification of eGFR Thresholds to Equalize Waitlist Time. J Am Soc Nephrol. 2021 Mar;32(3):677-685. doi: 10.1681/ASN.2020081144. PMID: 33622978; PMCID: PMC7920175.
Ladenheim, A., Tran, N., Roshanraven, B., and Young, B. (2021, April 29). Race and eGFR: Addressing Health Disparities in Chronic Kidney Disease. https://health.ucdavis.edu/blog/lab-best-practice/race-and-egfr-addressing-health-disparities-in-chronic-kidney-disease/2021/04
National Kidney Foundation. (n.d.) Understanding African American and non-African American eGFR laboratory results. https://www.kidney.org/atoz/content/race-and-egfr-what-controversy
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