Understand Your Kidneys’ Health and Take Steps to Protect Them

April 12, 2024

Your kidneys are two of the most important body organs. Think of your kidneys as a filter system for your body. The kidneys’ job is to remove toxic substances, also called waste products, from the blood and expel them from your body in urine. When your kidneys don’t perform as they should, these substances could accumulate in your blood and cause problems.

Creatinine, one of the most common waste products the kidney removes, is a standard measure of kidney function. It’s produced during the normal wear and tear of your muscles. While abnormal creatinine levels in your blood may point to kidney problems, diagnosing kidney disease involves much more than a blood test. Because creatinine levels in your blood can vary based on your age and body size, physicians have long relied on a formula that accounts for those factors, as well as race. Yet, race is not a biological factor, so its inclusion could overestimate kidney health in certain groups, predominantly Black and African American patients.

Here are three things to know about screening and diagnosing chronic kidney disease (CKD):

Who’s at risk for CKD, and how is it diagnosed?

Early-stage CKD doesn’t usually cause symptoms, so getting tested is the only way to understand how well your kidneys work. Some health conditions can put you at risk for kidney disease. If you have diabetes, heart disease, or a family history of kidney problems, your doctor may recommend a few blood tests, including a glomerular filtration rate (GFR) test. GFR is the standard way to measure creatinine levels. A GFR lower than 60 means your kidneys are likely not working as they should. Not sure if you’re at risk for kidney disease? Take the kidney health assessment quiz to find out if you are one of the 33% of adults in the U.S. who may be at risk for kidney disease.

How exactly is GFR measured?

A GFR can be measured directly, but it is a complicated test. It’s for that reason that GFR is most often estimated using a test called an estimated GFR or eGFR. It’s a mathematical formula that calculates your kidney function by comparing the results of your creatinine blood test and some information about you, such as age, weight, gender, and race. Researchers have included race in the eGFR formula for decades after discovering that Black study participants had higher creatinine levels than white participants despite having similar kidney functions. Researchers believed that Black people, on average, have more muscle mass than white people. The understanding at that time was that patients with more muscle mass make more creatinine. Thus, they concluded that Black patients’ eGFR should be adjusted with a factor to account for increased muscle mass.

Experts have since learned that race should be excluded from the eGFR calculation as it incorrectly estimates kidney function, making it seem better than it truly is. That’s because race is a social classification not rooted in biological or scientific elements. Overestimating eGFR in Black patients can potentially lead to delays in treatment, dialysis, and referral for kidney transplant evaluation.

Is race still included in the eGFR formula today?

According to new studies, there is no scientific basis for including race in these calculations, as doing so results in delayed care and worse clinical outcomes for Black patients. As a result, new guidelines by the National Kidney Foundation and the American College of Nephrology exclude race as a variable in eGFR calculations.

The takeaway.

When caught early, steps can be taken to help prevent further progression of CKD, including treating health conditions such as high blood pressure, diabetes, and other illnesses that pose a risk to your kidney. The latest national guidelines recommend a new version of the eGFR equation that removes race as a factor. All labs and clinical teams at CommonSpirit Health are advised to use this new equation to avoid missing the diagnosis of CKD in African-American patients. This is a significant step toward correcting the disparity in early diagnosis and ensuring that all communities receive equal treatment regardless of race or ethnicity.