Differential Morbidity by Ethnicity in Long-Term Survivors of Hematopoietic Cell Transplantation (HCT): A Report from the Bone Marrow Transplant Survivor Study (BMTSS)
Authors: Armenian Saro , Sun Can-Lan , Francisco Liton , Baker K. Scott , Forman Stephen J. , Bhatia Smita 
Published: April 2020

Abstract
Improvement in transplantation strategies have contributed to incremental change in post-HCT survival rates of 10% per decade; but this improvement is not enjoyed equally by all. Data from the CIBMTR (J Clin Oncol2005;23:7032–42) found Hispanics to be at a higher risk of treatment failure (relapse or death: hazard ratio [HR]=1.3, 95% confidence interval [CI], 1.1–1.5), when compared to non-Hispanic whites. According to the 2005 census, Hispanics form the largest ethnic minority group in the U.S., constituting 14.4% of the entire population. Compared to non-Hispanic whites, Hispanics are considered to be a vulnerable population for adverse health outcomes, due to reasons that include socioeconomic, cultural, and language barriers as well as barriers within the healthcare system. The purpose of this study was to determine the prevalence of and risk factors for chronic health conditions in a large population of Hispanic and non-Hispanic white HCT survivors. The BMTSS (a collaborative effort between City of Hope National Medical Center and University of Minnesota) examined self-reported chronic health conditions in individuals who underwent HCT between 1976 and 1998, and survived two or more years. A severity score (grade 1 through 4, ranging from mild to life-threatening or disabling) was assigned to each health condition according to the Common Terminology Criteria for Adverse Events (version 3). Some of the conditions graded as severe (grade 3) or life-threatening (grade 4) in this study included congestive heart failure, second malignant neoplasms, cerebrovascular accident, renal failure, and active chronic graft vs. host disease (GvHD). Adverse psychosocial outcomes were not included. Cox proportional-hazard models were used to estimate HR and 95% CI. The current study included 984 HCT survivors (443 [45.0%] allogeneic HCT and 541 [55.0%] autologous HCT recipients; 825 [83.8%] non-Hispanic whites and 159 [16.2%] Hispanics). Median age at study participation was 44.5 years (range, 18.2–73.0) for whites and 41.5 years (range 20.0–67.4) for Hispanics, and median follow-up was 7.3 years (range 2.0–27.8) and 8.0 years (range 2.5–25.2), respectively. There were no differences with respect to gender, BMI, presence of active chronic GvHD, relapse risk, and cancer surveillance practices, between the two ethnic groups. Hispanics were significantly less likely to have completed high school (55.1% vs. 96.6%, p&lt;0.001) and to be currently insured (75.9% vs. 93.7%, p&lt;0.001). Hispanics were significantly more likely to have undergone allogeneic HCT (67.9% vs. 52.5%; P&lt;0.01), and received the majority of their continued medical care at a cancer center (90.1% vs. 77.8%; p&lt;0.01). Hispanics were significantly less likely to report a chronic health condition of any severity (60.4% vs. 72.0%; p&lt;0.01). In fact, the cumulative incidence of a self-reported severe/life threatening chronic health condition was significantly higher for whites, when compared with Hispanics (54% vs. 41% at 10 years after HCT, p=0.02). After adjustment for age at HCT, gender, health insurance, primary diagnosis, type of HCT, exposure to TBI, length of follow-up after HCT, exposure to alcohol and tobacco, non-Hispanic whites were 1.34 (95% CI, 1.1–1.6) times as likely as Hispanics to report a chronic health condition; 1.38 (1.0–1.8) times as likely to report a mild/moderate condition; and 1.39 (1.1–1.8) times more likely to report a severe/life threatening condition. However, adjustment for education resulted in a mitigation of the ethnic differences, and the residual differences in chronic health conditions between whites and Hispanics were statistically non-significant (HR=1.18 [0.95–1.5, p=0.1], 1.13 [0.9–1.5, p=0.40, and 1.16 [0.9–1.5], respectively). This study demonstrates that the ability to self-report the presence of chronic health conditions may be a function of the educational status, and underscores the critical need for culturally adapted awareness of healthcare needs and issues among the educationally disadvantaged survivors, in order to improve their ability to seek and obtain adequate healthcare and reduce the associated morbidity and mortality.