Utilization of Autologous Hematopoietic Cell Transplantation Over Time in Multiple Myeloma: A Population-Based Study.

Purpose: Autologous hematopoietic cell transplantation (autoHCT) is associated with survival benefits in multiple myeloma (MM), but utilization remains low and differs by sociodemographic factors. Prior population-based studies have not fully captured autoHCT utilization or examined relationships between sociodemographic factors and autoHCT trends over time.

Patients And Methods: We used a novel data linkage between the California Cancer Registry, Center for International Blood and Marrow Transplant Research, and hospitalizations to capture autoHCT in a population-based MM cohort (n = 29, 109; 1991-2016). Due to interactions by treatment era, stratified multivariable Cox proportional hazards regression models determined factors associated with autoHCT.

Results: The frequency of MM patients who received autoHCT increased from 5.7% (1991-1995) to 27.4% (2011-2016). In models by treatment era, patients with public/no (vs. private) health insurance were less likely to receive autoHCT (2011-2016 Medicare hazard ratio (HR) 0.70, 95% confidence interval (CI): 0.63-0.78; Medicaid HR 0.81, CI: 0.72-0.91; no insurance HR 0.56, CI: 0.32-0.99). In each treatment era, Black/African American (vs. non-Hispanic White) patients were less likely to receive autoHCT (2011-2016 HR 0.83, CI: 0.72-0.95). Hispanic patients were less likely to undergo autoHCT, most prominently in the earliest treatment era (1991-1995 HR 0.58, 95% CI: 0.37-0.90; 2011-2016 HR 1.07, CI: 0.96-1.19). Patients in lower socioeconomic status neighborhoods were less likely to utilize autoHCT, but differences decreased over time.

Conclusions: Despite increases in autoHCT utilization, sociodemographic disparities remain. Identifying and mitigating barriers to autoHCT is essential to ensuring more equitable access to this highly effective therapy.