Racial differences in multiple myeloma survival: Associations with stem cell transplantation, insurance, and Medicaid expansion.

BACKGROUND: At the population level, Black patients with multiple myeloma (MM) may experience worse survival than White patients. The authors examined how autologous stem cell transplantation (ASCT), insurance, and Medicaid expansion relate to racial differences in real-world overall survival (rwOS). METHODS: Data from 4932 patients with MM (24% Black) in the Flatiron Health Research Database were analyzed using Cox regression (rwOS), Fine and Gray competing-risk models (ASCT), and polytomous regression (insurance). RESULTS: Adjusted for demographic and clinical factors, Black patients had worse rwOS than White patients (adjusted hazard ratio [aHR], 1.11; 95% confidence interval [CI], 1.00-1.23), which became nonsignificant when adjusted for ASCT and/or health insurance. Lack of ASCT was associated with inferior rwOS (aHR, 0.59; 95% CI, 0.51-0.67). Black patients were less likely to receive ASCT (younger than 65 years: adjusted subdistribution HR [asHR], 0.64; 95% CI, 0.57-0.72; 65 years and older: asHR, 0.54; 95% CI, 0.42-0.69) and experienced a longer time to transplantation. Medicaid expansion was associated with a lower likelihood of ASCT in patients younger than 65 years (aHR, 0.50; 95% CI, 0.38-0.67) and was three times more common among Black than White patients. Among patients who received oncology care, Medicaid expansion was not associated with changes in Medicaid coverage, ASCT receipt, or rwOS. CONCLUSIONS: Medicaid was associated with a lower likelihood of ASCT and was more prevalent among Black patients. Reduced receipt of ASCT was linked to inferior survival, contributing to survival disparities. Within this treated cohort, Medicaid expansion did not improve coverage, ASCT receipt, or survival, suggesting that structural barriers beyond insurance persist. Targeted efforts to improve ASCT access among Medicaid-insured patients are needed.