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Recognizing Racial Disparities Impacting Rare Kidney Disease Patients

MedpageToday

There's nothing more disheartening than seeing patients for the first time and knowing, had they come to me earlier, there may have been management strategies to help delay progression of their disease. As a Black physician, I am keenly aware of cultural tendencies in my community not to discuss or disclose to others, even family members, health issues one might be experiencing. I have seen this firsthand as a nephrologist in patients diagnosed with autosomal dominant polycystic kidney disease (ADPKD) -- particularly in patients of color. While ADPKD is a rare disease, it is the most common genetic kidney disorder affecting over 140,000 adults in the U.S.

ADPKD causes fluid-filled cysts to form in the kidneys that multiply and enlarge over time and can reach the size of a football. As these cysts grow, they replace normal kidney tissue, causing a decline in kidney function. The condition also becomes increasingly painful due to the stretching of the kidney capsule and excessive pressure on the lower spine.

ADPKD is also the fourth leading cause of end-stage kidney disease (ESKD), which can lead to dialysis or a transplant. Approximately half of individuals with ADPKD will reach ESKD by age 54 and three-quarters by age 62. Kidney failure occurs even earlier for Black and Hispanic patients.

Understanding Risk Factors

There are several reasons why patients of color may be misdiagnosed or diagnosed with ADPKD at a later stage in disease progression. Black and Hispanic people are disproportionately impacted by conditions that can potentially mask an ADPKD diagnosis such as hypertension and diabetes. In some cases, this may prevent ADPKD screening. For example, hypertension can confound diagnosis since it occurs in 50% to upwards of 70% of cases of ADPKD. In addition to making diagnosis more difficult, hypertension can be a contributing factor to higher rates of cardiovascular morbidity and mortality in ADPKD patients.

Since hypertension is more prevalent among Black people, there may be a tendency to assume it's due to environmental and lifestyle causes. However, if a patient has high blood pressure prior to age 35 and a family history of ADPKD, physicians should consider ADPKD and pursue further testing since Black patients may reach ESKD at an earlier age.

Another challenge with diagnosis is that patients with ADPKD can present with a normal or only slightly reduced estimated glomerular filtration rate (eGFR) even with significant progression of the disease. This is because healthy filtrating nephrons compensate for the damaged ones in the early stages of ADPKD. By the time kidney function begins to decline, irreversible damage to the kidney has already occurred. There is evidence that this decline can be more rapid among Black patients, especially when comorbidities such as type 2 diabetes and sickle cell anemia are present. Given the misleading results of eGFR in diagnosing and assessing the trajectory of the disease, it's critical to focus on kidney size rather than kidney function.

Other risk factors for patients include a family history of kidney failure before age 58, being overweight, and protein and albumin in the urine.

To assess the rate of disease progression, total kidney volume (TKV) needs to be measured through imaging such as ultrasound, MRI, or CT scans. Additionally, a genetic test would determine if the patient has the gene mutation so that family members can be informed of their risk. Referring patients early on to a nephrologist is critical for developing a plan of action to assess the trajectory of the disease and develop an action plan.

Beyond the physical factors impacting ADPKD diagnosis and progression, there are also structural and cultural obstacles that can affect patients of color. A person's access to medical care is a major determinant of treatment and outcomes. If uninsured or living in communities with few medical resources, there is a far greater chance that the patient will be in renal failure by the time the disease is diagnosed.

Prioritizing Family Conversations

Patients should be encouraged to have open conversations about ADPKD with family members who may carry the trait and should be screened as well. I find it can help to meet with family members to educate them about ADPKD and address their questions and concerns. Open conversations about the disease, as well as genetic screening to assess ADPKD risk, are especially critical for relatives planning to grow their families since each child has a 50% chance of inheriting ADPKD from a parent with the genetic trait.

It's important for patients to know that while ADPKD is a serious disease there are management strategies that can help. Taking the time to talk and listen to patients, and encouraging their questions is always essential for good health outcomes, but it's especially true for Black patients given historical and discriminatory practices that may cause them to distrust medical care.

I have also seen how important it can be for patients to connect with others with ADPKD to share experiences and support. I often refer patients to for information and resources to help guide them through their journey.

Gentzon Hall, MD, PhD, is an assistant professor of Medicine and Nephrology at Duke University School of Medicine in Durham, North Carolina. This article is sponsored by Otsuka America Pharmaceutical, Inc., for which Hall is a paid consultant.