Black patients with multiple myeloma have better survival than white patients when treated equally: a matched cohort study

We assessed differences in survival between non-Hispanic black (NHB) and non-Hispanic white (NHW) patients with multiple myeloma (MM), and the sequential effects of patient characteristics, and diagnosis and treatment-related factors on the survival disparity using data from 3319 NHB and 20,831 NHW MM patients in the SEER-Medicare (1999–2017) database. Four sets of 3319 NHWs were matched sequentially to the same set of 3319 NHBs, based on demographics (age, sex, year of diagnosis, marital status, and SEER site), socioeconomic status (SES, demographics plus SES), presentation factors (SES variables plus comorbidity), and treatment factors (presentation variables plus antimyeloma therapies). We found NHBs were less likely to receive treatment than NHWs even among patients matched for demographics, SES, and comorbidities. The absolute difference in 5-year survival between NHBs and NHWs was not significant in the demographics match (0.6%; P = 0.30) and remained non-significant after matching for SES (1.4%, P = 0.17). When matching for presentation, NHBs had significantly longer 5-year survival than NHWs (absolute difference = 3.8%, P = 0.003). Additional matching on treatment-related factors further enlarged the racial difference in 5-year survival to 4.6% ( P