Digging Deeper into Racial and Socioeconomic Disparities in Pediatric Heart Transplant

More scientific evidence is needed to guide these challenging, complex decisions

Numerous studies have identified that Black children have worse waitlist and post-transplant outcomes, but very few have examined why these disparities exist. Shahnawaz Amdani, MD, a pediatric heart failure and transplant cardiologist, is hoping to change that with research that is digging deeper into these disparities with the goal of guiding and improving clinical decision-making in pediatric heart transplant.

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Acknowledging disparities and prioritizing research

Two years ago, Dr. Amdani led an analysis that found Black children listed for heart transplant had a 25% higher risk of waitlist mortality than White children. In the first three years after transplant, they were also more likely to experience rejection episodes, as compared to White or Hispanic children.

“In 2023, there should be no reason that we don’t have enough scientific evidence to guide decision-making in pediatric heart failure and heart transplant. And if there is a question that’s unanswered, we need to find a way to answer those questions so that our patients and their parents know these high-stakes, complicated and clinically challenging situations are based on high-quality science.” 

The Pediatric Heart Transplant Society (PHTS) has made a commitment to prioritizing research related to racial and socioeconomic disparities in pediatric heart transplant. In 2020, the society launched the Healthcare Disparities Taskforce to better understand the role of social injustice within the discipline, promote cultural competency, provide education to clinicians and facilitate research into social determinants and outcomes. Dr. Amdani is a taskforce member in this initiative. His recent investigations offer new data and future directions to support these pursuits.  

Confronting clinician bias

The concept of clinician bias is not new. It’s been studied across various disciplines using a validated survey tool called the implicit association test (IAT). However, to date, no studies have examined bias in the setting of pediatric heart transplant, according to Dr. Amdani and colleagues.

To conduct their study, the team surveyed 500 transplant clinicians (physicians, surgeons, and allied health and nursing professionals) between June and August 2021. Of the 500 recipients, 91 (18.2%) completed the race IAT, 70 (14%) completed the socioeconomic status (SES) IAT, and 44 (8.8%) responded to both.

The IAT tests prompted respondents to sort stimuli into two race groups (White or Black) and two SES groups (upper class/lower class) and align with distinct attributes, such as good/bad or approach/avoid respectively, resulting in a composite score.

Race IAT scores revealed moderate levels of implicit bias (mean = 0.33, d = 0.76; P < 0.001), indicating a preference for White people, and socioeconomic IAT scores revealed strong implicit bias (mean = 0.52, d = 1.53; P < 0.001), or preference for people with higher SES. The study, which also assessed explicit bias, found weak levels of explicit bias toward race and socioeconomic status. However, it found an explicit preference for those with higher levels of education.

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They reported their findings in JACC: Heart Failure.

Dr. Amdani says acknowledging that bias exists among pediatric heart transplant clinicians is an important first step in eliminating it. Determining whether our implicit biases affect clinical decision-making is the next step. The team is planning a follow-up study using case vignettes that simulate real-world scenarios to help answer this question.

Community-level factors at the time of listing  

In a separate study, which appears in the Journal of Heart and Lung Transplantation, Dr. Amdani analyzed community-level risk factors to evaluate whether they are independently associated with worse outcomes in children undergoing heart transplantation.

“Where you live and the resources you have access to is very important, and these factors aren’t captured in research transplant registries. We wanted to understand if there is an association between community-level factors and clinical presentation in children who are listed for heart transplantation,” says Dr. Amdani.

Using the Scientific Registry of Transplant Recipients (SRTR), researchers extracted pediatric heart transplant data over a 10-year period, linking patients’ zip codes to the distressed communities index (DCI). The DCI, a tool developed by the Economic Innovations Group, provides a composite score based on several socioeconomic indicators tied to the health of a community. Based on a 1%-100% score, zip codes fall into one of five groups: Q1 (prosperous), Q2 (comfortable), Q3 (mid-tier), Q4 (at-risk) and Q5 (distressed).

In an analysis cohort of 5,293 pediatric heart transplant patients, researchers assessed the clinical outcomes of White, Hispanic and Black patients at each quintile. Here are their findings in summary:

  • Those in distressed communities were more likely to be Black and Hispanic, listed as Status 1A and have Medicaid insurance.
  • Compared to White males, Black males were more likely to present with advanced heart failure symptoms at the time of listing.
  • Children in the Northeast and Midwest were more likely than those living in the South to present with advanced heart failure symptoms at the time of listing.
  • Children from more distressed communities were more likely to present with advanced heart failure symptoms at the time of listing.

“Our findings suggest that socioeconomic disparities exist among children listed for heart transplant,” Dr. Amdani says. However, he cautions that this study is only capturing children who have been listed for transplant. “We have no idea of knowing who gets evaluated and not listed for heart transplant from these distressed communities.”

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Community-level risk factors and post-transplant outcomes

Dr. Amdani and colleagues have taken these findings one step further by creating their own novel pediatric community risk score to examine the impact of community level risk factors on post-heart transplant outcomes. Dr. Amdani received the Enduring Hearts/Pediatric Heart Transplant Society investigator award for this project.

They evaluated 18 community level risk factors and identified five risk factors that were associated with post-heart transplant graft loss: premature death rates in the community, ratio of population to primary care providers, childhood poverty in the neighborhood, binge/heavy drinking of alcohol and median household income in the neighborhood. These were used to develop the composite score.

Their findings, which Dr. Amdani presented at the 2022 American Heart Association Scientific Sessions Meeting, suggest that wide racial disparity exists in transplant outcomes among children from distressed communities undergoing heart transplantation. Their findings show that Black (but not White) children in distressed communities have significantly increased risk for post-transplant complications, including:

  • 33% greater risk of graft rejection
  • 66% greater risk of graft loss
  • 106% greater risk of experiencing cardiac allograft vasculopathy

“Using a novel pediatric specific community risk score, we were able to demonstrate that racial disparities are additive to socioeconomic disparities, such that Black children from the poorest neighborhoods have the worst transplant outcomes,” he says.

His motivation for this work and a message to colleagues

On his motivation for this work, Dr. Amdani says he is guided by a quote from Martin Luther King Jr.: “Of all the forms of inequality, injustice in healthcare is the most shocking and inhumane.”

His call to action to colleagues is straightforward. “As a community, we have to be very intentional over the next decade to close these disparities as it is unacceptable for us to let these continue,” says Dr. Amdani.