Access Has Improved for Diverse Patients Needing Umbilical Cord Blood Transplant, but Disparities Remain

Despite advancements in umbilical cord blood transplants, social determinants of health, such as poverty and public insurance, continue to impact outcomes.

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While umbilical cord blood transplants (UCBT) have improved survival rates for patients across all racial and ethnic groups, significant disparities persist, particularly for Latinx patients and those from high-poverty areas, according to new research published in Transplantation and Cellular Therapy.¹ Despite advancements, social determinants of health, such as poverty and public insurance, continue to impact outcomes, underscoring the need for equitable access to life-saving treatments.

Umbilical cord and placental blood are unique because they contain a high concentration of blood-forming cells.² A transplant procedure has the potential to be lifesaving, especially for individuals with rare conditions like acute myeloid leukemia (AML), acute lymphoid leukemia (ALL), or myelodysplasia, as examined in this study. Similar to a bone marrow transplant, a cord blood transplant replaces a patient's diseased cells with healthy ones.

Umbilical cord blood remains a crucial graft source for patients without matched donors, particularly for racial and ethnic minorities who often encounter challenges in finding adult-matched donors in national registries.¹ Despite declining usage due to the availability of haploidentical (haplo) and mismatched unrelated donor transplants, UCBT continues to offer a vital alternative, especially for specific patient populations.

Previous research from the Center for International Blood and Marrow Transplant Research (CIBMTR) found that Black patients had lower overall survival (OS) rates compared with White patients after receiving a single UCBT. The current study, utilizing a larger and more contemporary cohort, examines outcomes across racial and ethnic groups, comparing outcomes among White, Latinx, Black, and Asian patients to explore whether social determinants of health and matching UCB units by race and ethnicity impact transplant outcomes.

The researchers analyzed data from 2512 US patients, aged 1 to 80 years, who received either single or double UCBT for AML, ALL, or myelodysplasia. There were 983 patients who received a single UCBT and 1529 who received a double UCBT. Transplants were conducted after either myeloablative conditioning (n = 1752) or reduced intensity conditioning (n = 759). The primary outcome of the study was 2-year OS, while secondary outcomes included disease-free survival (DFS), transplant-related mortality (TRM), rates of acute and chronic graft-vs-host disease (GVHD), and GVHD-free, relapse-free survival (GRFS).

Outcomes Among Adults

Among 1705 adults, univariate analysis revealed some variation in 2-year OS rates across racial and ethnic groups. White patients had a 2-year OS of 41.5% (99% CI, 37.6–45.3), while Latinx patients had a lower OS of 36.1% (99% CI, 28.2–44.5). In contrast, Black and Asian patients had higher OS rates of 45.8% (99% CI, 36.7–55.1) and 44.5% (99% CI, 33.6–55.6), respectively.

Multivariate analysis demonstrated that Latinx patients had significantly lower OS compared with Black patients (P = .0005; HR, 1.45; 99% CI, 1.18–1.79). Despite this disparity, OS improved over time for all racial and ethnic groups, signaling advancements in UCBT practices. GVHD rates, including both acute and chronic forms, were similar across different racial and ethnic populations.

Outcomes Among Children

In the cohort of 807 children, univariate analysis showed that 2-year OS was highest for White patients at 66.1% (99% CI, 59.7–72.2), followed by Latinx patients at 57.1% (99% CI, 49–64.9), and Asian patients at 53.8% (99% CI, 32.7–74.2). Black patients had the lowest OS at 46.8% (99% CI, 35.3–58.4).

However, multivariate analysis revealed no statistically significant differences in OS among racial and ethnic groups (P = .051), suggesting that racial disparities in survival rates may be less pronounced in pediatric UCBT recipients. One notable finding the study highlighted was that Black children had a higher risk of severe (grade III/IV) acute GVHD compared with both White (P = .0016; HR, 2.25) and Latinx patients (P = .0016; HR, 2.17).

Analyzing the Role of Socioeconomic Factors

The results evaluating the impact of social determinants of health, such as poverty level, education, and insurance type, on UCBT outcomes demonstrated that Black and Latinx adult patients were more likely to reside in high-poverty areas, which was associated with worse OS (P = .03), largely driven by higher rates of TRM (P = .04). Conversely, educational attainment and insurance type did not significantly affect OS, GVHD, or other transplant-related outcomes.

For pediatric patients, the study showed children from high-poverty areas also experienced higher TRM (P = .02), although poverty did not significantly influence overall survival, DFS, or other posttransplant outcomes. Additionally, public health insurance, such as Medicaid, was linked to increased TRM in children (P = .02), highlighting the potential challenges faced by economically disadvantaged families in securing optimal health care resources.

Race and Ethnicity Matching: No Survival Benefit

A key finding of the study exhibited that matching the race and ethnicity of UCB units to patients did not provide a survival advantage for either children or adults. The researchers noted that the success of UCBT may be more dependent on other factors, such as the quality of the transplant process and posttransplant care, rather than racial or ethnic matching between donors and recipients.

“We find that OS has improved over time for all races and ethnicities and is comparable now between Black and White patients,” the researchers concluded. “For adults, OS improvement for Latinx patients has lagged behind improvement in OS for other races and ethnicities. Latinx patients have a higher incidence of ALL compared to other racial and ethnic groups, and may have more aggressive disease, with higher risk mutations.”

References

1. Ballen K, Wang T, He N, et al. Impact of race and ethnicity on outcomes after umbilical cord blood transplantation. Transplant Cell Ther. 2024;30(10):1027.e1-1027.e14. doi:10.1016/j.jtct.2024.07.009

2. Options for umbilical cord blood banking & donation. Health Resources & Services Administration: Blood Stem Cell. Updated March 2024. Accessed October 16, 2024. https://bloodstemcell.hrsa.gov/donor-information/donate-cord-blood/options-umbilical-cord-blood-banking-donation#:~:text=Blood%20from%20the%20umbilical%20cord,is%20saved%20for%20that%20family.