Under-representation of black patients with multiple myeloma in studies supporting International Myeloma Working Group guidelines

Introduction: Multiple myeloma (MM) is more common in Black persons when compared to non-Hispanic White persons. The International Myeloma Working Group (IMWG) provides consensus for diagnosis and treatment of MM. Our study aimed to assess the racial composition of supporting studies used by IMWG to publish their guidelines Methods: We performed a cross sectional study that included all IMWG publications up to July 2022. References cited in each publication were reviewed. Review articles, comments, editorials, case reports, and animal-based studies were excluded. Results: A total of 59 IMWG publications with 3956 references were reviewed. Final analysis included 2047 references of which 39 % (n = 804) were clinical trials, 35 % (n = 712) were observational studies, 20 % (n = 401) were diagnostic and or genetic testing-based studies, 3 % (n = 65) were population-based analysis and 3 % (n = 65) classified as others. Only 10.4 % of included references (n = 213/2047) reported race/ethnicity of studied patients. The total number of patients in all referenced studies were 5,747,920, only 2.6 % (n =150,790) black patients. Of the trials referenced and done exclusively in the US, 41 out of 282 (14.5 %) reported race/ ethnicity with a total number of patients of 38,050 of which 2493 (6.5 %) were black patients. Conclusion: IMWG guidelines were based mainly on studies that did not include enough Black patients. Guidelines should consider inclusion of observational, diagnostic and population-based studies with more black patients to allow for better reflection of disease prevalence, clinical characteristics and/or outcomes.