Diagnosing and staging CKD involves using a calculation known as estimated glomerular filtration rate (eGFR). Current eGFR calculations use a person’s race, age, sex, and serum creatinine levels to determine how the kidneys are functioning. However, researchers at the National Institutes of Health (NIH) have proposed eliminating race as a variable. Learn more about why it should be changed and how research shows how kidney function can be fairly measured.

What Is the Concern with A Race Variable?

In studies performed in the 1990s, Black Americans, on average, were found to have a higher serum creatinine level in their blood, independent of kidney function. This led to eGFR calculations being adjusted specifically for ‘Black’ patients. However, experts at NIH believe this could lead to a misdiagnosis and systematic bias. 

“Using race as a testing factor risks kidney disease misdiagnosis. There is great variance within the genetic ancestry of people who identify as ‘Black’, which means we cannot reliably view ‘Black’ people as being from a single ancestral group,” said Afshin Parsa, M.D., NIDDK program director for Chronic Renal Insufficiency Cohort (CRIC). “Misdiagnosis could lead to a person receiving incorrect drug dosing or delays in receiving dialysis or a kidney transplant. Current eGFR calculations could be exacerbating racial inequities in a disease that disproportionately affects Black people, so this study set out to identify factors that wouldn’t rely on including a person’s race to calculate eGFR.”

What could fix this disparity?

The CRIC is a longstanding nationwide study funded by NIH. From the data, researchers analyzed and found a potential new way to calculate eGFR without the race-dependent marker, serum creatinine. Cystatin C could be used in place of it as an unbiased and accurate means to measure kidney function. 

“An accurate eGFR formula that does not rely on self-reported race is a huge leap forward for all people with, and at risk for, chronic kidney disease,” said NIDDK director Griffin P. Rodgers, M.D. “NIDDK is committed to addressing health disparities, and we hope this study’s findings lead to positive changes in how CKD is identified and treated—helping address the risk of systemic bias and error in diagnosing and treating a disease that already disproportionately affects Black people.”

*NIH-supported study suggests alternative to race-based kidney. (2021, September 23). National Institutes of Health (NIH). https://www.nih.gov/news-events/news-releases/nih-supported-study-suggests-alternative-race-based-kidney-function-calculations