Background: Despite a lower incidence of non-Hodgkin’s lymphoma (NHL) and specifically diffuse large B-cell lymphoma (DLBCL), the most common histologic subtype, previous studies suggest that blacks have a higher disease-specific mortality from NHL than whites. To study this disparity, we looked at the impact of race, treatment delays and the use of rituximab on survival in NHL and DLBCL. To control for access to care, we focused on a population of patients with Medicare benefits.
Methods: After establishing a SEER-Medicare Data-Use Agreement and obtaining IRB approval, we used the linked SEER-Medicare database for NHL patients diagnosed from 1995 through 2002, with claims data through 2003. Multivariable logistic regressions were used to assess the difference between race and rates of survival, NHL histology, and the likelihood of receiving treatment within 90 days and of receiving rituximab at any time during the course of NHL treatment.
Results: Among 41,704 NHL cases, 35,014 (85%) cases were in whites and 2,287 (5.5%) were in blacks. Of the 14,831 total cases of DLBCL, 12,449 (84%) were in whites and 715 (4.8%) were in blacks. Despite a lower incidence of NHL, blacks had a lower 1-year survival for NHL compared to whites (OR 0.68 [95% CI 0.61–0.76]). Blacks also had a lower 1-year survival for DLBCL compared to whites (OR 0.63[95% CI 0.53–0.75]). Patients treated within 90 days of diagnosis had improved 1-year survival for NHL (OR 1.10 [95% CI 1.03–1.18]) and for DLBCL (OR 1.60 [95% CI 1.47–1.75]). When controlling for age, gender and income, blacks were less likely than whites to be treated within 90 days of a NHL diagnosis (OR 0.599 [95% CI 0.526–0.681]). The use of rituximab was associated with improved 1-year survival for NHL (OR 3.67 [95% CI 3.37–4.00]) and specifically for DLBCL (OR 3.01 [95% CI 2.66–3.40]). However, blacks were significantly less likely to receive rituximab for NHL (OR 0.55 [95% CI [0.47–0.63]) and specifically for DLBCL (OR 0.71[95% CI 0.57–0.90]). An analysis of two and three year survival for NHL and DLBCL yielded similar results for the impact of race, treatment delays and use of rituximab.
Conclusions: Blacks are diagnosed with NHL and specifically DLBCL less frequently than whites but have significantly lower 1-year survival rates. Blacks were significantly less likely to begin treatment within 90 days of a NHL diagnosis. In addition, blacks were significantly less likely to receive rituximab despite presumed equal access to healthcare with Medicare benefits. The reason for this racial disparity is unclear. Studies to further characterize the disparity are needed.
Disclosure: No relevant conflicts of interest to declare.