Why is chronic kidney disease risk higher for Black people?

Kidney disease risk is far higher for African Americans than for other groups. The reasons for that are complex.
September 13, 2022
Medical and lifestyle management of diabetes and hypertension are important for reducing the risk of chronic kidney disease among Black people.
Medical and lifestyle management of diabetes and hypertension are important for reducing the risk of chronic kidney disease among Black people. Photo: Getty Images.

Two organs small enough to fit inside a pair of cupped hands exert an outsized influence on our health. They are the bean-shaped kidneys — workhorse wonders that silently eliminate waste from the body and keep fluids in proper balance when they are in good shape. But when they begin to fail, the kidneys become the source of multiple problems, including high blood pressure, cardiovascular disease, stroke, anemia and early death.

The source of these problems, chronic kidney disease (CKD), is common. Medical experts at the Centers for Disease Control and Prevention estimate that 37 million people in the United States suffer from it. Chronic kidney disease requires medications, treatment for related conditions, and in the most serious cases, dialysis and kidney transplant. The disease erodes the quality of life for patients even as it imposes a formidable financial burden – to the tune of $87 billion in 2019 for Medicare beneficiaries alone, according to the CDC. Treating beneficiaries with kidney failure, or end-stage renal disease, tacked on another $37 billion in 2019.

Dr. Jessica Kendrick, kidney specialist at UCHealth, says many factors account for the increased risk of kidney disease for African Americans. Photo courtesy TBD.
Dr. Jessica Kendrick, kidney specialist at UCHealth, says many factors account for the increased risk of kidney disease for African Americans. Photo courtesy TBD.

The human cost of CKD is not borne proportionately. Hispanic and Native American people, for example, are at higher risk for kidney failure than white people. But the risk is, by far, the highest for African American people – nearly four times that of white people. African Americans make up 13% of the United States population, but 35% of all people in the country with kidney failure.

The reasons for this disparity and unequal burden are varied, intertwined and sometimes surprising. For more information, UCHealth Today spoke with Dr. Jessica Kendrick, a kidney specialist who practices at the UCHealth Kidney Disease and Hypertension Clinic – Anschutz Medical Campus. Dr. Kendrick has also published research on health risks and barriers to care among African American people and other minorities.

Do you see and treat a high percentage of African Americans in the Kidney Disease Clinic?

“Yes. In my own practice, about 20% or more of my patients are African Americans,” Kendrick said. That compares with an African American population of about 10% in the Denver area, she noted.

What are the primary medical reasons for chronic kidney disease in African Americans?

“The two most common factors are diabetes and with hypertension,” both of which also affect African Americans disproportionately, Kendrick said.

Does genetics play a role as a risk factor?

It can, but in a much smaller group of people. Variations from both parents in the APOL1 gene – which emerged in regions of West Africa as protection against sleeping sickness – are associated with a ninefold increase in risk of end-stage renal disease among those with a first-degree relative who carries the mutations, Kendrick said.

“We’ll do genetic testing if some people in a patient’s family have the disease and if they want it,” she added. “It’s a factor to consider.”

Genetics aside, don’t we have effective treatments for both diabetes and hypertension?

Yes. “We can prevent complications with kidney-protective medications that slow the progression of the disease and help to prevent people from going on dialysis,” Kendrick said. Angiotensin II receptor blockers (ARBS) lower blood pressure by relaxing vessels, while SGLT2 inhibitors help to decrease blood sugar levels in patients with Type 2 diabetes.

Those sound like relatively simple solutions. Are there barriers for African Americans that complicate the problem?

Kendrick emphasized that for all patients, “it’s super important to have a conversation so that they understand why they have kidney disease, why they are at risk and that we have to work together to improve their outcomes.” She noted that like hypertension, kidney disease approaches silently, with few symptoms until the disease has progressed dangerously. “Sometimes that gets lost,” Kendrick said.

That said, Kendrick noted that some Black people and other racial minorities face socioeconomic barriers, including lack of access to insurance, primary care, healthy food, reliable transportation, housing and opportunities for healthy activity. As a result, Kendrick said, “many of these patients present later, with more advanced disease, because they haven’t had appropriate treatment throughout.”

What are some of the ways providers can help to break down these barriers?

There are multiple pathways, Kendrick said. For example, she and her colleagues join with social workers and pharmacists to address the cost of medications for patients with limited resources. As for medical care, she added, “Patients are complex. There is no way we can do this if we don’t work in a collaborative environment.” That requires communication with primary care, endocrinology, and cardiology specialists. Dietitians also play an important role in discussing healthy food choices, such as restricting phosphorus, potassium and sugar with patients.

Kendrick added that she relies heavily on her nurses to help educate patients about their disease and the medications they take. With that work, nurses also play a vital role in addressing health literacy – another potential barrier for people of lower socioeconomic status, Kendrick said.

“I encourage patients to bring people with them to their visits and record our conversations. We also write out a lot of information to take home,” she said.

Finally, Kendrick acknowledged that establishing trust with African American CKD patients can be “a big issue” for kidney specialists, the vast majority of whom are white. The roots of African American distrust in the health care system in general run deep and were most recently exposed during the COVID-19 pandemic.

How can that distrust be broken down?

“Cultural competency training is really important,” Kendrick said. “We’re doing more of it in medical school and residency now, but we need to do more. Too often it is written off.”

She added the Division of Renal Diseases and Hypertension at the University of Colorado School of Medicine conducts cultural competency training and work on addressing health care disparities.

Kendrick herself co-authored a 2015 paper that focused on primary care providers who treated minority patients with hypertension. One key finding: most of those surveyed agreed with the notion that disparities in race, ethnicity and socioeconomic status played a role in the hypertension care that patients receive. But far fewer than half said that these disparities affected their own patients. They were more likely to point to their patients’ behaviors as the cause of the disparities. Kendrick argued for “increasing provider awareness of disparities within the local health setting to improve hypertension control for minority patients.”

“There is no doubt there is implicit bias among providers” in treating African Americans and other minorities, Kendrick said. “But if you recognize it, that’s how you move forward.”

The changes she suggests include lengthening early visits with patients in order to gain trust; explaining chronic kidney disease and the patient’s goals for managing it; asking about family, hobbies and other topics to create rapport; identifying barriers to health, such as food insecurity and insurance access; discussing medications and why they are important; and keeping communication open after the visit.

“It’s never easy,” Kendrick said. “The care must be very individualized.”

How might the ‘implicit bias’ among providers that you speak of manifest itself in treating African American patients with chronic kidney disease?

One important way is that African American patients are referred less often than others for kidney transplants, Kendrick said. She co-authored a 2018 study based on interviews with adult hemodialysis patients in the Denver area. The interviews revealed that fewer African Americans received an evaluation for a kidney transplant than did white and Hispanic people. The paper called for “timely referral by providers” and better transplant education to shrink the disparities. A more recent study – among others – reached a similar finding, while focusing on the biases and social determinants of health that account for the disparity.

Kendrick pointed to the Hispanic Kidney Transplant Program, established at UCHealth University of Colorado Hospital – Anschutz Medical Campus, as a model for boosting the number of transplant referrals and evaluations. The program, established in 2018 by Kendrick’s colleague, Dr. Monica Grafals, focuses on employing patient outreach, education, engagement and communication to successfully improve those numbers. Kendrick and Grafals co-authored a paper this year that described the findings and favorably compared the experiences of patients before and after the clinic was established.

“Something similar to this clinic could be done for other communities, including African Americans,” Kendrick said.

Are there other reasons for disparities in care for African Americans with chronic kidney disease?

Yes, but there is some good news on at least one of them, Kendrick said. It revolves around estimated glomerular filtration rate (eGFR), a standard method for measuring how well kidneys function, and establishing the stage of disease. Kendrick explained that the test measures levels of creatinine, a waste product of muscle activity. A high level of creatinine is a sign of the kidneys failing to do their waste-filtering job as well as they should.

For many years, Kendrick said, the medical community adhered to a notion that African Americans have higher creatinine levels because they have more muscle mass than white people. “Because of that we thought we needed a different equation for them. That stuck. We all learned it.” The result was that eGFR reports adjusted for race, as well as age, sex, body weight and other factors.

Kendrick noted that in recent years, numerous groups, including medical students at the University of Washington, questioned using the race formulation in measuring eGFR. They pointed out that race has nothing to do with biology and using it as a consideration in calculating kidney disease fails to account for individual characteristics in African Americans, including socioeconomic status and other social determinants of health. The result, they argued, was that fewer African Americans may have been diagnosed with kidney disease and referred for kidney transplants.

What was the result of the reevaluation of eGFR?

It led to the National Kidney Foundation and the American Society of Nephrology establishing a joint task force to examine including race in the eGFR calculation. Last September, the joint task force recommended dropping “the race variable” from the equation. “It’s more accurate and is what we now use,” Kendrick said.

Why is the new calculation important for African Americans?

“We are now classifying more people with kidney disease than we did before,” Kendrick said. “We are treating them earlier, which means we will see benefits in the long run.”

What else can be done to address chronic kidney disease among African Americans?

It’s vital that health care providers acknowledge that it’s an urgent problem and that they play a role in addressing it, Kendrick said. “You have to be uncomfortable if you’re going to make changes,” she added.

As a member of the National Kidney Foundation, Kendrick said that she advocates for speaking directly to community members about kidney disease and transplant and conducting more screenings and follow-up. These efforts, in addition to providing superior medical care, are necessary to change the trajectory of kidney disease and death for African Americans, she said.

“It is a quality-improvement problem that we have to fix, and if we don’t talk about it, it won’t get changed,” Kendrick concluded.

About the author

Tyler Smith has been a health care writer, with a focus on hospitals, since 1996. He served as a writer and editor for the Marketing and Communications team at University of Colorado Hospital and UCHealth from 2007 to 2017. More recently, he has reported for and contributed stories to the University of Colorado School of Medicine, the Colorado School of Public Health and the Colorado Bioscience Association.