SAN DIEGO – Bone marrow transplants can be lifesaving for patients with acute myeloid leukemia, but new research shows how socioeconomic factors are creating barriers to treatment and higher death rates for people living in underserved communities.
A scientific team led by researchers at Fred Hutchinson Cancer Center followed AML patients at academic and community treatment centers. They found that patients from underserved areas were both more likely to die without a bone marrow transplant and less likely to receive one compared with people from more educated and affluent communities. Specifically, living in a neighborhood with a lower education level led to 33% lower odds of receiving a bone marrow transplant, a statistically significant effect. In contrast, the survival rate after transplantation was not significantly different for people from underserved communities.
The findings, presented Sunday at a press conference at the annual meeting of the American Society of Hematology, suggest that accessibility rather than efficacy of the therapy is the main issue facing patients from lower socioeconomic backgrounds. The study authors added that, to their knowledge, this is the first study to examine in depth how specific socioeconomic variables influence AML patients’ chances of receiving a bone marrow transplant and survival after treatment.
“I think the findings are novel in the sense that it involves a very large patient population from multiple centers,” said Jeff Auletta, senior vice president of health care equity for the National Marrow Donor Program, who was not involved in the work . “It really digs deeper into some of these social determinants of health as barriers to access for patients.”
AML is responsible for approximately one-third of leukemia cases in adults, and the American Cancer Society estimates that nearly 21,000 people will be diagnosed with the disease this year and that it will kill approximately 11,200 people in the United States.
Although the main treatment for the disease is chemotherapy, a hematopoietic cell transfer, also called a bone marrow transplant, offers patients the best chance for a cure. This infusion of blood-forming stem cells, administered after chemotherapy, replenishes a patient’s immune system. And when these new cells are donated by someone else, they recognize any remaining cancer cells as foreign invaders and attack them.
AML is the most common condition for bone marrow transplants worldwide, and some studies have found that the five-year survival rate for AML patients who receive a bone marrow transplant is about 65%, compared to 24% among those who do not receive the therapy.
While work from the past has shown that factors such as age, health and frailty can influence a patient’s chance of accessing treatment, the authors of the current study wanted to better understand the effects of socio-economic status. So they followed nearly 700 AML patients over time at 13 academic and community treatment centers, including Stanford, Washington University in St. Louis, Duke and Fred Hutch’s own cancer center. About 43% of patients were female, 86% were white, 3% Asian and 6% black.
The researchers looked at the impact of four measures of socio-economic status on patients’ chances of receiving a transplant, death without a transplant and death after therapy. These measures, based on the zip code in which a patient lived, were the proportion of people with less than a high school education; fraction of households receiving Supplemental Nutrition Assistance Program benefits (formerly known as food stamps); the share of homes that receive a supplementary security income; and poverty rate.
The authors found that patients were more likely to die without a transplant if they came from areas where more residents did not have a high school diploma or received SSI, monthly payments for people with disabilities, or older adults with little to no income. These factors led to a statistically significant increased risk of death of 21% and 41%, respectively.
Those from areas with lower education levels were significantly less likely to receive a bone marrow transplant. Patients with higher rates of SSI and SNAP use were also less likely to receive a transplant, but those effects were close to, but not quite, statistically significant.
The authors found that patients from neighborhoods with elevated levels of one of four measures of low socioeconomic status had a slightly higher risk of dying after transplant, but none of these effects were significant.
That finding is in contrast past research This suggests that AML patients from neighborhoods with high poverty rates are more likely to die after receiving an allogeneic bone marrow transplant, although that previous finding came from children and the recent study was conducted in adults.
“The way we interpret it [is that] if patients are able to overcome the barriers to transplantation… results could perhaps be comparable to those of patients from other socio-economic backgrounds,” said Natalie Wuliji, lead author of the study.
Wuliji, a hematologist-oncologist at Fred Hutch who performs bone marrow transplants, says there are many ways that socioeconomic status can create barriers for patients. Receiving and recovering from a transplant can take months and requires a patient to stay near a treatment center and have a caregiver. That requires time away from work and, in many cases, finding a hotel or other temporary accommodation for those not yet near a treatment center.
Understanding the full benefits and risks of these intensive treatments can also be difficult for patients with less education, she added, a challenge that is compounded if doctors are biased against patients from underserved communities.
Wuliji noted that the study suggests that some ways of measuring socioeconomic status are more robust than others. For example, income may be an obvious benchmark, but assessing whether someone has government benefits can better identify patients who have been living in poverty for a longer period of time and face the greatest barriers.
In the future, the group wants to confirm its findings in additional, larger groups of patients. The researchers also plan to look at the impact of having an available caregiver on access to and outcomes of bone marrow transplantation, and to test pilot strategies to identify patients facing socioeconomic barriers and target interventions to them to offer.