Race and Socioeconomic Status Influence Outcomes of Unrelated Donor Hematopoietic Cell Transplantation

Abstract

Success of hematopoietic-cell transplantation (HCT) can vary by race, but the impact of socioeconomic-status (SES) is not known. To evaluate the role of race and SES, we studied 6207 unrelated-donor myeloablative HCT recipients transplanted between 1995–2004 for acute or chronic leukemia or myelodysplastic syndrome. Patients were reported by transplant center to be White (n=5253), African-American (n=368), Asian/Pacific-Islander (n=141), or Hispanic (n=445). Patient income was estimated from residential ZIP Code at time of HCT. Cox-regression analysis adjusting for other significant factors showed that African-American (but not Asian or Hispanic) recipients had worse overall survival (OS) (relative-risk [RR] 1.47 (95% CI 1.29–1.68), P<0.001) compared to Whites. Treatment-related mortality (TRM) was higher in African-Americans (RR 1.56, (1.34–1.83), P<0.001) and in Hispanics (RR 1.30, (1.11–1.51), P=0.001). Across all racial groups, patients with median incomes in the lowest quartile (<$34,700) had worse OS (RR 1.15 (1.04–1.26), P=0.005) and higher risks of TRM (RR 1.21 (1.07–1.36), P=0.002). Inferior outcomes among African-Americans are not fully explained by transplant-related factors or SES. Potential other mechanisms such as genetic polymorphisms that impact drug metabolism or unmeasured co-morbidities, socioeconomic factors and health behaviors may be important. Low SES, regardless of race, has a negative impact on unrelated donor HCT outcomes.

Racial differences in allogeneic hematopoietic cell transplantation outcomes among African Americans and whites

“…Although the percentage of African Americans among other ethnic groups varied significantly among recent transplant studies, 23,31 this number is comparable to the larger CIBMTR studies 22,30 as well as to past leukemia studies 13,14 and indicative of our current leukemia/hematologic malignancy population. Despite this, we acknowledge that the absolute number of African Americans in this study is small, and, given this, the study may lack the power to detect significant racial differences.…”

“…In contrast to the previous study, however, socioeconomic status in and of itself was found to be associated with worse unrelated donor HCT outcomes independent of race. 22 Another more recent study from the CIBMTR 31 also reported worse survival outcomes, attributed to more severe acute GvHD, among African Americans (29%) compared with whites (13%) undergoing HCT for aplastic anemia. In contrast, another large registry study demonstrated a difference in survival rates in Hispanics, but not in African Americans, compared with whites after allogeneic HCT for AML, ALL and CML.…”

“…22,23,[29][30][31] A study from the Fred Hutchinson Cancer Institute found poorer OS among African Americans compared with whites after HCT for hematologic and non-hematologic malignancies, primarily attributed to a higher risk of severe acute GvHD (37% African Americans versus 21% whites). 23 Their analysis also demonstrated increased time interval from diagnosis to transplantation among African Americans compared with whites, even among sibling donors, raising the possibility of delayed referral and resistance to referral to HCT.…”

“…It has been previously reported, however, that racial and ethnic minorities who received HCT have worse survival when compared with whites. [22][23][24] Although several potential reasons have been postulated as above, there remain insufficient data to explain the racial differences in outcome after HCT. We thus undertook this retrospective analysis at our center to study the race-related survival after HCT in hopes of better identifying potential prognostic factors to account for poor outcome.…”

Nonbiological factors affecting survival in younger patients with acute myeloid leukemia

“…The treatment of AML is prolonged, expensive, and complex. It is conceivable that patients who are not married and have a low income have a more fragile support network with which to cope with the physical, material, and emotional challenges of AML treatment, thereby affecting access to and outcomes of postremission therapy (including HSCT) 31,32 and the treatment of recurrent disease. Yet another possibility is that patients with unfavorable NBFs also have more serious comorbidities affecting their opportunity to benefit from aggressive therapy.…”