“Previous studies have found that patients in underrepresented race/ethnicity groups and with lower socioeconomic status have worse outcomes after blood and bone marrow transplants,” said Dr. Stephanie Lee, a professor in the Clinical Research Division at Fred Hutchinson Cancer Center. Stem cell transplants—using stem cells from a donor—are essential treatments for blood cancers like lymphoma and leukemia. However, these types of transplants also come with a substantial risk of a serious and potentially fatal side effect called graft-versus-host disease (GVHD)—a complication where the donor’s immune system attacks the patient’s cells and tissues. For people with GVHD, long-term care can be necessary, as well as prolonged immunosuppressive treatment and monitoring for complications. These specialized treatments and close monitoring are possible only if people have access to them, but racial and ethnic minority groups have a greater proportion of people with lower socioeconomic status, making it harder for them to access the needed health care services. “Health disparities have been attributed to greater difficulty in finding a completely matched stem cell donor, a higher incidence of complications like graft-versus-host disease (GVHD), less resources to recover if complications occur, and other factors,” commented Lee. “It [GVHD] is treated with immunosuppressive medications and can result in serious morbidity and death.” In a recent Blood Advances publication, Dr. Lee and her team investigated the relationships between race/ethnicity or lower socioeconomic status with overall patient survival, relapse, and treatment-related mortality after diagnosis of GVHD.
“Whenever we look, we almost always find racial/ethnic and socioeconomic status health disparities in blood and marrow transplantation, and it turns out we see the same pattern in people who have GVHD” commented Lee. From this particular study, the investigators showed that there were significant differences in important outcomes, such as relapse and survival, for the non-Hispanic Black group or the lower income groups compared to other groups. These findings were based on data from the Center for International Blood and Marrow Transplant Research, a national stem cell transplant registry, which was used by the researchers to compare data from non-Hispanic Blacks, Hispanics, Asians and non-Hispanic Whites (reference cohort) who underwent blood and marrow stem cell transplantation between 2008-2018. “In our study of more than 6,000 adults who developed acute GVHD, we found that the non-Hispanic Black group had more severe acute GVHD, higher treatment-related mortality and lower survival than the non-Hispanic White group. The lowest socioeconomic status group had an increased risk of blood cancer relapse. In a similar number of patients who all had chronic GVHD, we did not see survival or relapse differences in race/ethnicity groups, but we did see lower treatment-related mortality and better survival in the highest socioeconomic status group,” Lee explained. In this study, lower socioeconomic status was associated with poorer transplant outcomes after diagnosis of GVHD, regardless of race/ethnicity.
“We do not have data on actual income, so we had to estimate income from zip code,” Lee pointed out as one of the limitations of this study. “Although we took into account major transplant factors like type of donor and disease status, we don’t have information about the stressors that people dealt with during the transplant procedure, such as housing, transportation, childcare and other factors,” Lee added. These factors may also affect patient outcomes.
Dr. Lee and her team are keen to understand why these differences exist, and to test interventions that will give all people the same opportunity to have a successful transplant. “Transplantation techniques are evolving, and new donor sources are being used allowing more people from underrepresented racial/ethnic groups to find donors and have transplants,” Lee commented. “We would like to repeat this study in a few years to see if race/ethnicity and SES are still associated with these outcomes using the newer techniques,” Lee added. “There is also interest in trying to mitigate health disparities by providing more resources and better support to patients and their caregivers. Prevention of severe GVHD continues to improve and might be especially helpful for the non-Hispanic Black group.”
The spotlighted work was funded by the National Cancer Institute, National Heart, Lung and Blood Institute, National Institute of Allergy and Infectious Diseases, Health Resources and Services Administration, and the Office of Naval Research.
Fred Hutch/University of Washington/Seattle Children's Cancer Consortium member Dr. Stephanie Lee contributed to this work.
Farhadfar N, Rashid N, Chen K, DeVos JD, Wang T, Ballen KK, Beitinjaneh A, Bhatt VR, Hamilton BK, Hematti P, Gadalla SM, Solomon SR, El Jurdi N, Lee CJ, MacMillan ML, Rangarajan HG, Schoemans HM, Sharma A, Spellman SR, Wingard JR, Lee SJ. 2024. Racial, Ethnic and Socioeconomic Diversity and Outcomes of Patients with Graft-versus-Host Disease: A CIBMTR Analysis. Blood Adv.