SAN DIEGO — Bone marrow transplants can be lifesaving for patients with acute myeloid leukemia, but new research reveals how socioeconomic factors create barriers to treatment and higher death rates for people living in disadvantaged communities.
A scientific team led by researchers at Fred Hutchinson Cancer Center tracked AML patients across academic and community treatment centers. They found that patients from disadvantaged areas were both more likely to die without a bone marrow transplant and less likely to receive one compared to people from more-educated and affluent communities. Specifically, living in a neighborhood with lower education levels led to 33% lower odds of receiving a bone marrow transplant, a statistically significant effect. In contrast, the survival rate after a transplant was not significantly different for those from disadvantaged communities.
The findings, presented on Sunday during a press briefing at the American Society of Hematology’s annual meeting, suggest that access rather than therapy efficacy is the main issue facing patients from lower socioeconomic backgrounds. The study’s authors added that, to their knowledge, this is the first study to take an in-depth look at how specific socioeconomic variables affect AML patients’ odds of getting a bone marrow transplant and survival after treatment.
“I think the findings are novel in the sense that it’s a very large patient population from multiple centers,” said Jeff Auletta, senior vice president of health equity for the National Marrow Donor Program, who was not involved in the work. “It really drills down on some of these social determinants of health as being access barriers for patients.”
AML accounts for about a third of adult leukemia cases, and the American Cancer Society estimates that nearly 21,000 people will be diagnosed with the disease this year and around 11,200 will die from it in the United States.
While the main treatment for the disease is chemotherapy, a hematopoietic cell transfer, also known as a bone marrow transplant, offers patients their best shot at a cure. This infusion of blood-forming stem cells, given after chemo, replenishes a patient’s immune system. And when these new cells are donated from another person, they recognize any lingering 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 given a bone marrow transplant is around 65%, compared to 24% among those who don’t get the therapy.
While past work has shown that factors like age, health, and frailty can affect a patient’s chance of accessing treatment, the authors of the current study wanted to better understand the effects of socioeconomic status. So they tracked nearly 700 AML patients over time across 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 socioeconomic status on patients’ chance of receiving a transplant, dying without one, and dying after the therapy. Those measures, based on the ZIP code a patient lived in, 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 receiving Supplemental Security Income; and poverty rate.
The authors found patients were more likely to die without a transplant if they came from areas with more residents lacking a high school diploma or receiving SSI, monthly payments for people who are disabled or older adults with little to no income. These factors led to a statistically significant 21% and 41% increased risk of death, 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 usage were also less likely to receive a transplant, but those effects were nearly but not quite statistically significant.
The authors found that patients from neighborhoods with elevated levels of any of the four measures of low socioeconomic status had slightly higher risks of dying after transplant, but that none of these effects were significant.
That finding stands in contrast with past research suggesting that AML patients from neighborhoods with high poverty levels are more likely to die after receiving an allogeneic bone marrow transplant, though that earlier finding is from children and the recent study was done in adults.
“The way we interpret it [is that] if patients are able to overcome the barriers to transplant … perhaps the outcomes could be comparable to patients from other socioeconomic backgrounds,” said Natalie Wuliji, the study’s lead author.
Wuliji, a hematologist-oncologist at Fred Hutch who does bone marrow transplants, says there are many ways socioeconomic status can create barriers for patients. Getting and recovering from a transplant can take months and requires that a patient stay nearby a treatment center and have a caretaker. That requires time away from work and, in many cases, finding a hotel or other temporary accommodations for those not already 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 made worse when physicians are biased against patients from disadvantaged communities.
Wuliji noted that the study suggests some ways of measuring socioeconomic status are more robust than others. Income, for example, may be an obvious metric, but assessing whether someone is on government benefits may better identify patients who’ve been living in poverty for prolonged periods of time and face the greatest barriers.
Going forward, the group is looking 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 transplant, and to test pilot strategies to identify patients facing socioeconomic hurdles and offer them targeted interventions.
