Survival Disparities in Patients with Lymphoma According to Place of Residence and Treatment Provider: A Population-Based Study

Abstract

Objectives: We evaluated the association of the primary area of residence (urban vs. rural) and treatment (trt) provider (university-based vs. community-based) with overall survival in patients with lymphoma, and determined if there are patient subgroups that could benefit from better coordination of care.Methods: We performed a population-based study in 2,330 patients with centrally confirmed lymphoma from Nebraska and surrounding states reported to the Nebraska Lymphoma Study Group between 1982 and 2006. Patient residential ZIP codes at the time to trt were used to determine rural/urban designation, household income and distance to trt center; while trt providers were categorized into university-based or community based. Multivariate analyses were used to group patients into risk levels based on 8 factors found to be associated with survival at the time of trt (age, performance score, Ann Arbor stage, presence of B symptoms, LDH levels, tumor bulk, nodal and extranodal involvement). The following categories were identified: low-risk (1–3 factors), intermediate risk (4–5 factors), and high-risk (≥6 factors). Cox proportional regression analyses, stratified by type of lymphoma (low-grade NHL, high-grade NHL and Hodgkin) were used to evaluate the association between place of residence and trt provider with overall survival.Results: Among urban residents, 321 (14%) were treated by university-based providers (UUB) and 816 (35%) were treated by community-based providers (UCB). Among rural residents, 332 (14%) were treated by university-based providers (RUB) and 861 (37%) were treated by community-based providers (RCB). Patients from rural areas were more likely to be older and Caucasian, with a lower median household income, greater travel distance to seek trt, and more likely to have high-risk disease when compared to patients from urban areas. In multivariate analysis, using all patients regardless of risk level, the relative risk of death (RR) among UUB, UCB and RUB was not statistically different. However, RCB had a higher risk of death RR 1.37, 95% CI 1.14–1.65, p=0.01; RR 1.18, 95% CI 1.04–1.33, p<0.01; and RR 1.26, 95% CI 1.06–1.49, p=0.01 when compared with UUB, UCB and RUB, respectively. This association remained true in both low- and intermediate-risk patients. Among high-risk patients, both RUB and RCB were at higher risk of death when compared with UUB or UCB, while UCB were not different from UUB. We found no differences in progression-free survival according to place of residence and trt provider. The use of stem cell transplantation was significantly higher in patients coming from urban and rural areas treated by university-based providers (UUB 19%, RUB 16%) compared to urban and rural patients treated by community-based providers (UCB 11%, RCB 10%, p < 0.01). Patients from rural areas (RUB and RCB) were slightly less likely to die from lymphoma-related causes than patients from urban areas (75% versus 80%, p=0.04).Conclusion: Overall survival in patients with lymphoma is inferior in patients coming from rural areas. This relationship varies according to treatment provider and pretreatment risk levels. Further studies in patients from rural areas are needed to understand how coordination of care is carried to design appropriate interventions that may improve the disparity noted.