Despite enduring disparities, stem cell transplants expand across all races, ethnicities
Click Here to Manage Email Alerts
Key takeaways:
- HSCT volume, survival has increased for all races and ethnicities over time.
- Survival disparities remain for African American patients after allogeneic transplant.
The amount of autologous and allogeneic hematopoietic stem cell transplants for hematologic disorders has increased over time in tandem with longer survival, according to results of an observational study.
Researchers observed improvements across all racial and ethnic groups but found that disparities related to treatment outcomes still exist.
The findings, published in Blood Advances, show non-Hispanic African American patients, both children and adults, had significantly higher mortality rates after receiving allogeneic transplants than white individuals of the same age groups.
“We were pleasantly surprised to see signs of progress in the field with [increasingly] higher rates of transplants in minorities, as well as survival outcomes for Hispanic patients being comparable to non-Hispanic whites,” Nandita Khera, MD, MPH, professor of medicine at Mayo Clinic, told Healio. “But with the suboptimal outcomes in non-Hispanic African Americans, we know we still have a lot of work to do.”
Background and methodology
The number of autologous (auto-HSCT)and allogeneic hematopoietic stem cell transplants (allo-HSCT) has risen over the years and been accompanied by improvements in treatment outcomes, according to background information provided by researchers.
However, there has been a lack of research on how that growth has impacted underserved communities.
“Although prior large studies using registry data from Center for International Blood and Marrow Transplant Research (CIBMTR) and some institutional studies have shown improvements in outcomes post-transplant, they have not reflected on trends by racial or ethnic background,” Khera said.
There have been several documented reasons for outcome disparities among patient populations following HSCT, including comorbidities, lack of donor sources, socioeconomics and health system-related factors.
Efforts have been made to reduce those inequities, including better education, improved referral and selection procedures, expansion of donor pools, and public health care policies, but the procedure’s success among different racial and ethnic groups needed further evaluation, according to researchers.
“Other registry studies that examined racial [and] ethnic trends have examined outcomes in patients before the year 2010,” Khera said. “A lot of progress has been made in the last decade in the field of HCT, which we felt would have implications for impact on outcomes by race [and] ethnicity. We wanted to see if the increased volume of transplants and improved outcomes have benefited all the racial [and] ethnic groups equally.”
Researchers used data from the CIBMTR, which has patient information from nearly all HSCT recipients in the U.S.
They built their study cohort based on information collected between 2009 and 2018 on auto-HSCT in adults and allo-HSCT in adults and children.
Researchers separated HSCT recipients into four racial categories — non-Hispanic African American, Hispanic, non-Hispanic white and other.
They analysis included 79,904 auto-HSCTs and 65,662 allo-HSCTs.
Results and next steps
The volume of auto-HSCTs and allo-HSCTs increased annually over the study period, and individuals from historically undeserved communities had a growth rate two to three times larger than white patients for both transplant types, particularly for African Americans and Hispanics.
“Some of the volume increase is attributed to the proportional increase in overall populations of these groups as the rate of growth of population is higher in these groups compared [with] non-Hispanic whites,” Khera said. “But some of it is also likely from multipronged approach of scientific advances, such as understanding mechanisms for disparity in outcomes, novel strategies to widen the donor pool with availability of alternative donor sources, improved graft-versus-host disease prevention and supportive care, with policy and society initiatives to help expand access to HCT and improve outcomes.”
OS increased for all individuals after auto-HSCTs and allo-HSCTs over time, and all races and ethnicities had similar mortality rates following auto-HSCT.
However, after allo-HSCT, African American adults had a mortality risk 13% higher than white adults, and African American children had a 62% greater risk for death compared with white children.
Hispanic patients did have comparable OS with white patients after allo-HSCT, which substantiates progress based on previous studies.
Study limitations included lack of data on Asian, Native American and Pacific Islander populations, as well as information on the number of individuals who could benefit from HSCT, rather than only those who received it.
Khera stressed the need for more research to understand why African Americans had worse mortality risks following allo-HSCT.
“More qualitative work is needed to understand the reasons for continued disparities for our non-Hispanic African American patients in terms of exploring the impact of individual level and system level factors that may contribute to the disparity,” she said. “Fortunately, there are initiatives in the field such as ACCESS initiative, which is a collaboration between American Society of Transplantation and Cellular Therapy and National Marrow Donor Program to help mitigate disparities by focusing on better understanding of disparities and addressing modifiable factors through multistakeholder collaborations.”
For more information:
Nandita Khera, MD, MPH, can be reached at khera.nandita@mayo.edu.
Collapse
Click Here to Manage Email Alerts