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FOR THE PUBLIC

Understanding race & eGFR

equity graphic

On June 27, 2022, the OPTN Board of Directors unanimously approved the proposal Establish OPTN Requirement for Race-Neutral eGFR Calculations. The policy was implemented July 27, 2022.

Review the proposal and the public comments.

You may already know about the estimated glomerular filtration rate (eGFR), or you may be unaware of how some doctors use it in their assessment of their patients.

The OPTN Kidney Transplantation Committee and Minority Affairs Committee put a proposal out for public comment Jan. 27 – March 23, 2022, that aimed to establish OPTN requirements for race-neutral eGFR calculations for the purposes of pre-transplant evaluation. This proposal was unanimously approved by the board and was implemented on July 27, 2022. 

These committees are made up of patients and professionals. They sought input from the broader transplant community, including patients and those who care for them, so that any possible changes would incorporate feedback from all stakeholders. Review this FAQ for more information about race and eGFR, then learn more about the policy development process.

What's on this page?

This page contains information to help you:

In the sections below, you will learn about:

  • The estimated glomerular filtration rate (eGFR), a common clinical calculation that measures the function of patients’ kidneys
  • How race-based adjustments to the eGFR have been used to evaluate kidney patients
  • How current OPTN policy uses eGFR in relation to a patient’s waiting time
  • How OPTN policy changes have addressed how race is used in eGFR for purposes of transplant
  • A glossary of key terms
“The patient's input in transplant policy is valuable - our lived experience with a transplant helps to improve allocations for better transplant implementation.” — Precious McCowan, OPTN Kidney Transplantation Committee member,
kidney transplant recipient, donor mother

What is eGFR?

The estimated glomerular filtration rate, or eGFR for short, measures how slowly or quickly kidneys remove a waste product called creatinine from the blood. This calculation helps doctors understand how sick a kidney patient is.

There are actually a number of different eGFR calculations, and they don’t all use the same factors. Different transplant hospitals can use different eGFR formulas when they try to determine how sick their patients are.

Did the OPTN develop eGFR calculations?

No, the OPTN did not develop any of the eGFR calculations currently used, but eGFR values are used throughout OPTN transplant policy. For example, a kidney candidate’s eGFR is used as one of several ways to determine when the patient is able to start adding waiting time on the transplant waiting list. More details about what OPTN policy says about eGFR can be found below.

Race-based adjustments to eGFR

What is the Black race variable in eGFR?

A variable is part of a formula. One of the most widely used formulas for measuring eGFR includes a Black race variable. This formula is the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI). There are additional formulas that also use a Black race variable.

The CKD-EPI formula can use as many as four patient-specific variables:

  • Creatinine clearance (how quickly your kidneys can filter waste products from your blood)
  • Age
  • Gender
  • Race (when race is used as a variable, patients are categorized as Black or Not Black)

The Black race variable was established from study results, which showed that Black patients had higher levels of creatinine.[1]

In order to adjust for these assumed differences, some eGFR formulas include a Black race variable that automatically increases all Black patients’ eGFR values.

Do all eGFR formulas use a Black race variable?

No, not every eGFR formula uses a Black race variable. There are a number of different eGFR calculations, and they don’t all use the same factors. Different transplant hospitals can use different eGFR formulas. Hospitals are required to use eGFR formulas without a Black race variable, effective July 27, 2022.

What does using a race variable mean for patients?

Recent research[2] suggests that using a Black race variable in eGFR could actually disadvantage Black patients with chronic kidney disease. For example, studies suggest that using the variable in the CKD-EPI formula has the potential to overestimate Black patients’ kidney function by as much as 16 percent. Some researchers and clinicians also question the design of the original studies that led to the development of the Black race variable[3].

Why is it a problem to overestimate a patient’s kidney function?

It’s a problem to overestimate a patient’s kidney function because it means they could appear to be less sick on paper than they actually are. This especially matters in relation to when candidates start to get waiting time. For adult candidates who are not on dialysis, eGFR values must be less than or equal to 20 mL/min to start waiting time.

Patients with overestimated eGFRs may take longer to access waiting time on the transplant waiting list. The overestimation of Black patients’ eGFRs could also lead to poor management of chronic kidney disease, as well as overall worse outcomes for those patients[4]. Read the committees’ co-sponsored proposal for more information.

In this broad example (which uses the CKD-EPI equation), Candidate A is categorized as Black and Candidate B is categorized as not-Black. They are identical for all patient-specific variables except for race.

Factors Candidate A Candidate B
Sex: Male Male
Age (years): 60 60
Black Race: Yes No
Serum Creatinine (mg/dL): 3.3 3.3
eGFR (mL/min/1.73m2):: 23.3 19.2

As a result of the Black race variable in the example shown here, the not-Black Candidate B’s eGFR is 19.2, so he would qualify to start to get waiting time.

Because the Black Candidate A’s eGFR is above 20, he would not start to get waiting time, and his eGFR might have been overestimated.

What does OPTN policy say about eGFR?

GFR values are used as qualifying thresholds for adult kidney candidates throughout OPTN policy. Most notably, eGFR is used as a qualifier for beginning waiting time on the kidney transplant list. Under the previous policy, there were no specifications as to which calculations should or should not be used to meet eGFR qualifying thresholds in OPTN policy. The changes to policy approved on June 27, 2022, require use of a race-neutral calculation, effective July 27, 2022. 

How is eGFR used as a qualifying threshold for waiting time?

Patients older than 18 years old have to meet one of the following three requirements before they can start to get waiting time:

  • They receive regularly administered dialysis for end-stage renal disease (ESRD)
  • They have an eGFR of less than or equal to 20 mL/min
  • They have a creatinine clearance of less than or equal to 20 mL/min

Does my eGFR prevent me from being listed as a candidate for transplant?

No. OPTN policy states that a kidney transplant candidate may be registered to the transplant waiting list with any eGFR. However, no candidate will start waiting time until they meet one of the above qualifications. Some transplant hospitals may have their own protocols for referral, so be sure to ask your transplant hospital when you can be registered to the transplant waiting list.

Why is this important in terms of equity?

The use of eGFR as a threshold for starting to get waiting time is important, because it can impact how much waiting time a kidney patient accrues.

The amount of waiting time a kidney patient has accrued is critical - it plays a big role in the prioritization of kidney offers. If the Black race variable was used to calculate a patient’s eGFR, they may have to wait longer to reach the threshold to get waiting time. This would disadvantage Black patients trying to access transplant.

What else should I know about the race variable in eGFR?

GFR calculators with race variables only offer two response options: “Black” or “Not Black.”

These two options do not allow for mixed race or multi-racial individuals, and do not account for the existing genetic diversity within the Black population.

did my doctor use the Black race variable to calculate my eGFR?

The answer to this question will depend upon the transplant program where you are registered. Your doctor is the best resource to answer this question. The OPTN does not collect this information.

Glossary

Chronic

Developing slowly and lasting for a long time, possibly the rest of the person’s life. For example, chronic kidney disease (CKD).

Creatinine

Found in the blood, it is a waste byproduct of muscle. Creatinine level in the blood is one of the key measures of how well kidneys work.

End-stage renal disease

A disease that leads to the permanent failure of a kidney or kidneys.

Medical urgency

The amount of risk to a candidate’s life or long-term health without receiving an organ transplant. The sicker the patient, the greater their medical urgency.

Transplant hospital

A hospital that performs transplants. Transplant hospitals qualify patients for transplant, register patients on the national waiting list, perform transplant surgery and provide care before and after transplant.

Waiting time

The amount of time a candidate is on the wait list. Waiting times can be influenced by many factors, including blood and tissue type, the size of a candidate, medical urgency, the distance between the donor’s hospital and the potential donor organ, and an individual transplant hospital’s criteria for accepting organ offers.

Public comment

An important step in the policy making process. Public comment for OPTN policy happens twice a year and ensures that the perspectives and concerns of the general public are taken into account and addressed in policy proposals.

Qualifying threshold

In transplant, this is the level or value that has to be reached before a patient will start to get waiting time.

Background: How the eGFR project developed

Providing equity in access is required by the OPTN statute and regulation and the eGFR project intends to improve equity by potential racial bias.

In 2021, the OPTN formed a Reassess Race in eGFR Calculation Workgroup to study the use and impact of a race-based adjustment to the calculation.


1 Levey AS, Bosch JP, Lewis JB, Green T, Rogers N, Roth D. A More Accurate Method To Estimate Glomerular Filtration Rate from Serum Creatinine: A New Prediction Equation. Annals of Internal Medicine. 1999. 130(6): 461-470

2 Eneanya ND, Yang W, Reese PP. Reconsidering the Consequences of Using Race to Estimate Kidney Function. American Medical Association. 2019. 322(2):113-114

3 Eneanya ND, Yang W, Reese PP. Reconsidering the Consequences of Using Race to Estimate Kidney Function. American Medical Association. 2019. 322(2):113-114

4 Ahmed S, Nutt CT, Eneanya ND, Reese PR, Sivashanker K, Morse M, Sequist T, Mendu ML. Examining the Potential Impact of Race Multiplier Utilization in Estimated Glomerular Filtration Rate Calculation on African-American Care Outcomes. Journal of Should I General Internal Medicine. 2020. 36(2):464–71DOI: 10.1007/s11606-020-06280-5