Racial Differences in Utilization of Hematopoietic Cell Transplantation for Lymphoma in the United States

Abstract

<h3>Introduction</h3> Racial disparities have been documented in hematopoietic cell transplantation (HCT), a complex and expensive therapeutic modality for hematologic malignancies. Prior work suggests that racial minorities in the US have lower rates of utilization of HCT compared to White patients. However, the available literature on racial disparities in HCT is limited, particularly with regard to lymphoma patients. <h3>Objectives</h3> The objective of this study was to determine if racial differences exist in utilization of HCT for lymphoma by comparing transplant activity to disease incidence rates between 2013-2016. <h3>Methods</h3> This was a retrospective cohort study using publicly available data from the Center for International Blood and Marrow Transplant Research; Surveillance, Epidemiology, End Results program; and US Census Bureau. All patients in the US who underwent HCT for Hodgkin lymphoma (HL) and Non-Hodgkin lymphoma (NHL) between 2013-2016 were included. Patients with unknown race or multiple races were excluded. We assessed transplant utilization by calculating the transplant utilization rate (TUR) for each disease, separately. Rates were operationalized as the number of transplants performed per 100 new cases of the disease diagnosed in the US during the same time period. <h3>Results</h3> There were a total of 18,569 transplants for HL and NHL included. Table 1 shows patient characteristics by transplant type. During the same time period, age-adjusted incidence rates [95% confidence interval (CI)] for HL for Whites, Blacks, Asians/Pacific Islanders (API), and American Indians/Alaska Natives (AI) were 2.65 (2.59-2.71), 2.61 (2.46-2.77), 1.24 (1.14-1.36), and 1.00 (0.73-1.34) cases/100,000 persons at risk, respectively. Incidence rates were higher for NHL for the same racial groups at 20.22 (20.05-20.38), 14.44 (14.06-14.82), 13.53 (13.16-13.90), and 8.75 (7.82-9.75), respectively. Transplant and incidence data were consistent from 2013-2016. There were no significant differences in TURs for HL between racial groups. However, Whites with NHL had a higher TUR than Blacks [7.02 (95% CI 6.90-7.13) vs 4.75 (95% CI 4.49-5.02), p < 0.001], which was due to differences in utilization of autologous rather than allogeneic HCT [5.77 (95% CI 5.67-5.88) vs. 3.56 (95% CI 3.33-3.79), p < 0.001 for autologous HCT and 1.24 (95% CI 1.20-1.29) vs. 1.19 (95% CI 1.06-1.33), p = 0.488 for allogeneic HCT]. Figure 1 shows the utilization data for both HL and NHL. The impact of this difference in utilization of autologous HCT was an estimated loss of 143 transplants per year for Black patients. <h3>Conclusion</h3> Autologous HCT for NHL is underutilized for Black patients compared to White patients in the US. Additional research is needed to understand the reasons for this difference.