What the New eGFR Calculation Means for Your Kidney Disease Diagnosis and Treatment

In the past, some medical calculations, like the estimated glomerular filtration rate (eGFR), included race in their estimates. After countless hours of research, analysis, and discussion, the National Kidney Foundation and the American Society of Nephrology eGFR Task Force recommended a new race-free approach to measuring eGFR. 

What does this new equation mean for patients, especially those who identify as Black or African American? Two of the Task Force members, Dr. Mallika L. Mendu, MD, MBA, and Glenda Roberts, a kidney disease patient, helped make this change happen and are here to break it down.

The estimated glomerular filtration rate (GFR) is a quick way to assess how well the kidneys filter toxins from the blood, balance fluids, control the production of red blood cells, and more. To find the eGFR, healthcare professionals use a blood test and a special calculator.

After rigorous scientific study, discussion, and patient input, the Task Force recommended using the new eGFR 2021 CKD EPI Creatinine Equation. This calculation, originally published by Dr. Inker in the New England Journal of Medicine, uses creatinine and cystatin C to estimate kidney function without using race. It has been endorsed by the United States Pathology and Laboratory Society Leadership and The Organ Procurement Transplantation Network (OPTN) who unanimously agreed to require transplant hospitals to use the new race-neutral calculation. 

"One of the points that we made over and over again in the task force discussion is that race is a social construct. It's not a biological construct," Glenda said. "By removing it from the equation, we have acknowledged the fact that we want to look at biological factors that might impact kidney disease."

Before changing the equation, the inclusion of race could increase the eGFR of those who self-identified as African American or Black. This meant that the estimated kidney function showed a better result than it was in reality. Overestimating kidney function could have severe consequences, like prescribing or dosing medicines incorrectly, misusing contrast dyes, and delaying necessary treatment.

Glenda experienced this firsthand: "As a patient when I looked at the old equation that included the race modifier, it elevated my eGFR by 16%. That impacted my ability to get on the transplant list by as much as two years."

The new equation put Glenda in the lower range to move forward with that life-changing treatment.

While people who identify as Black or African American are 13% of the population, they account for 35% of those with kidney failure in the United States. Removing race from the eGFR equation is a start but not the end of the work that needs to be done to end the disparity.

"Unfortunately, those statistics have not improved over a significant period," said Dr. Mendu. "Black patients are also less likely to get home dialysis, less likely to get a transplant, and they have worse clinical outcomes when it comes to things like high blood pressure and other related complications of kidney disease. So it raises the question of why."

As the task force investigates this question, they'll also focus on increasing kidney disease education and researching biomarkers of kidney disease, like creatinine and cystatin C, for a reliable way to check kidney function. 

"We need more research and education, but particularly research in this phase to make sure that we continue to look at this question of how we're estimating GFR and that we're doing so accurately and without any bias," said Dr. Mendu. "We also need to continue research efforts in the area of health care disparities where we know there are major socioeconomic disparities, particularly for patients with kidney disease. So this is just the start of this process."

Learn more about health disparities.

These changes may take time to go into effect; however, we've updated our patient and healthcare resources, including our eGFR calculator, to reflect a non-race-based eGFR. 

To use the calculator, you will need the serum creatinine value from your latest laboratory tests. Should the eGFR calculator suggest you have later-stage kidney disease than previously, speak with your doctor to see if your kidney disease treatment needs to change. 

Use the new eGFR calculator. 

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