Racial Disparity in Mortality Rates Among Black and White Americans with Multiple Myeloma

Background: In the United States, Multiple myeloma (MM) is the second most common hematologic malignancy and the most common hematologic malignancy in blacks. It is a fatal plasma cell dyscrasia with a median overall survival of 5 to 10 years. Different studies have highlighted a racial disparity in survival outcomes between Blacks and Whites patients' population with MM. However, the reason for the observed racial disparity in survival outcomes is not clearly understood.

Aim: To explore the role of socioeconomic variables including access to insurance and, median Income on the racial disparity in outcome among patients with MM.

Method: We conducted a retrospective analysis of all hospitalizations associated with the primary diagnosis of MM in the National Inpatient Sample (NIS 2008-2014) database using the relevant International Classification of Diseases, Ninth Revision, Clinical Modification codes. The study outcome was the mortality rates between black patients and a propensity score matched control group of white patients with MM.

Result: There were 185,000 MM associated hospitalization in the NIS (2008-2014). Among the study population, 66.7% were whites, 20.8% were blacks, and 7.7% were Hispanics. The mean age was 66.5 years for blacks and 70.2years for whites. Among the Black population, 21.6% had private insurance compared to 25.1% of their White counterparts. Also, 45.6% of Black participants were in the lowest income quartile compared to only 19.6% of Whites. Only 13.5% of Blacks were in the highest income quartile compared to 28.7% of Whites. 73.4% of Blacks were on public insurance compared to 70.9% of Whites. There was no difference in the mortality rate between blacks and a control group of whites matched for insurance, median income, sex and age (49.4% vs 50.6%, p =0.42).

Conclusion: Multiple myeloma may not be more deadly in Blacks compared to Whites, and the observed disparity in outcomes in the literature are likely due to the effects of social determinants of health such as income and access to insurance.