Despite the increasing use of hematopoietic stem cell transplant as curative therapy for children with cancer and other life-threatening diseases, new research suggests that children who undergo a transplant for cancer may be more likely to die of treatment-related complications if they live in poorer neighborhoods. The study, published by Kira Bona, MD, MPH, and colleagues in the journal Blood, also found that having Medicaid vs private insurance was associated with inferior outcomes in these patients. Researchers said the results underscore the need to better understand and mitigate the effects of poverty and other social determinants of health on pediatric cancer care.

Kira Bona, MD, MPH

Hematopoietic stem cell transplantation is a high-resource treatment option accessible only at some medical centers. Together with radiation therapy or chemotherapy, a hematopoietic stem cell transplant is designed to increase the chance of eliminating the cancerous or abnormal blood cells and of restoring normal blood cell production.

Analysis Findings

Children younger than age 18 with cancer who live in communities with high poverty rates had a 34% greater risk of treatment-related mortality following hematopoietic stem cell transplant compared with children in low-poverty areas. Even after adjusting for a child’s disease and transplant-related factors, the data revealed children on Medicaid had a 23% greater risk of dying of any cause within 5 years of undergoing hematopoietic stem cell transplant and a 28% greater risk of treatment-related mortality when compared with children who had private insurance.

“Our study shows that even after children with cancer have successfully accessed this high-resource treatment at specialized medical centers, those who are exposed to poverty are still at higher risk of dying of complications after treatment and of dying overall,” said lead author Dr. Bona, Attending Physician, Dana-Farber/Boston Children’s Cancer and Blood Disorders Center. “Simply providing the highest quality complex medical care to children who are vulnerable from a social perspective is inadequate if our goal is to cure every child with cancer.”

One in five children in the United States lives in a household with an income below the federal poverty level. Although previous studies have shown an association between household poverty and poorer outcomes in hematopoietic stem cell transplant procedures generally, there are limited data on how poverty influences the success of hematopoietic stem cell transplant in children specifically.

Study Methods

Dr. Bona and her team sought to fill this gap by reviewing outcomes data for pediatric allogeneic transplant recipients from the Center for International Blood and Marrow Transplant Research Database, the largest available repository of hematopoietic stem cell transplant outcomes. The researchers looked at two cohorts of patients: 2,053 children with malignant disease and 1,696 children with nonmalignant disease, who underwent a first transplant between 2006 and 2015.

Neighborhood poverty exposure was defined according to U.S. Census definitions as living within a ZIP code in which 20% or more of the residents live below 100% of the federal poverty level. They also stratified patients by type of insurance and used Medicaid as a proxy measure for household level poverty. The researchers looked at pediatric patients’ overall survival, defined as the time from hematopoietic stem cell transplant until death from any cause, as well as relapse, transplant-related mortality, acute and chronic graft-vs-host disease, and infection in the first 100 days following hematopoietic stem cell transplant.

More Key Points

The researchers found neighborhood poverty or having Medicaid insurance did not seem to affect outcomes among children transplanted for nonmalignant diseases such as sickle cell disease, including overall survival, relapse, or infection. Dr. Bona said the study does not explain why this might be, and more research is needed; however, it is possible that physicians and families of children with nonmalignant conditions who face social health challenges may elect to avoid intensive hematopoietic stem cell transplant procedures.

One study limitation is its reliance on proxy measures of household poverty (ZIP code and Medicaid insurance), which do not provide insight into specific aspects of children's socioeconomic exposures and the home environment in which they live that; these aspects may interfere with their ability to navigate the health-care system. Dr. Bona noted that researchers and clinicians have historically not considered social determinants of health as being as important as biologic variables in specialized cancer care, and so they have not collected data on these factors as part of research. She called this a missed opportunity.

“We as a field need to recognize that nonbiologic variables—such as your exposure to poverty and other social determinants of health—matter just as much as many of the biologic variables we pay close attention to when thinking about outcomes for children, and these variables must be collected systematically for research if we want to optimize the care and outcomes of the children we serve,” said Dr. Bona.

If future studies could collect more nuanced measures of poverty—such as household material hardship (eg, food insecurity, access to heat and electricity, housing insecurity, transportation insecurity) or language barriers—targeted interventions in the form of assistance programs could potentially help mitigate social hardships and improve the overall care of children with cancer.

Disclosure: For full disclosures of the study authors, visit ashpublications.org/blood.