Blacks are more likely to develop multiple myeloma and die from the disease than whites.1 Despite blacks are reported to have a lower utilization rate of novel therapeutic agents than whites, whether this translates into poorer outcomes remains unclear.2-7
We conducted this analysis with the most recent data from the Surveillance Epidemiology and End Results (SEER)-Medicare database with 3,319 black and 20,831 white patients with myeloma, to examine the extent of the racial disparities in multiple myeloma survival in the U.S., with the added objective to understand the nature of the disparity. We asked whether white patients with myeloma who present similar to black patients with myeloma receive similar therapies as blacks and if not, to what extent treatment differences explain the disparities in survival.
To address these questions while avoiding limitation of conventional model-based methods, we used a novel tapered matching approach8 to compare the entire population of black patients in the SEER-Medicare database with four matched white populations, 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 blacks were less likely to receive treatment than whites even among patients matched for demographics, SES, and comorbidities. Black patients had a similar median survival compared with white patients (30.0 vs. 32.0 months; P = 0.61), as well as a similar 5-year survival rate (29.7% vs. 30.3%; P = 0.30). The absolute difference in 5-year survival between blacks and whites remained non-significant after matching for SES (1.4%, P =0.17). However, when matching for presentation, blacks had significantly longer 5-year survival than whites (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 < 0.001).
In summary, in the SEER-Medicare population, blacks with multiple myeloma were less likely to receive novel antimyeloma treatment compared with whites, and these disparities in treatment could not be explained by sociodemographic factors. Although the overall survival was comparable between blacks and whites across the entire population, blacks had a better survival when they were treated similar as whites.
References
- Waxman AJ, Mink PJ, Devesa SS, Anderson WF, Weiss BM, Kristinsson SY, et al. Racial disparities in incidence and outcome in multiple myeloma: a population-based study. Blood. 2010;116(25):5501-5506.
- Fiala MA, Wildes TM. Racial disparities in treatment use for multiple myeloma. Cancer. 2017;123(9):1590-1596.
- Ailawadhi S, Parikh K, Abouzaid S, Zhou Z, Tang W, Clancy Z, et al. Racial disparities in treatment patterns and outcomes among patients with multiple myeloma: a SEER-Medicare analysis. Blood Adv. 2019;3(20):2986-2994.
- Ailawadhi S, Aldoss IT, Yang D, Razavi P, Cozen W, Sher T, et al. Outcome disparities in multiple myeloma: a SEER-based comparative analysis of ethnic subgroups. Br J Haematol. 2012;158(1):91-98.
- Derman BA, Jasielec J, Langerman SS, Zhang W, Jakubowiak AJ, Chiu BC. Racial differences in treatment and outcomes in multiple myeloma: a multiple myeloma research foundation analysis. Blood Cancer J. 2020;10(8):80.
- Fillmore NR, Yellapragada SV, Ifeorah C, Mehta A, Cirstea D, White PS, et al. With equal access, African American patients have superior survival compared to white patients with multiple myeloma: a VA study. Blood. 2019;133(24):2615-2618.
- Costa LJ, Brill IK, Brown EE. Impact of marital status, insurance status, income, and race/ethnicity on the survival of younger patients diagnosed with multiple myeloma in the United States. Cancer. 2016;122(20):3183-3190.
- Dong J, Gu X, El-Serag HB, Thrift AP. Underuse of Surgery Accounts for Racial Disparities in Esophageal Cancer Survival Times: A Matched Cohort Study. Clin Gastroenterol Hepatol. 2019;17(4):657-665 e613.
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