Higher mortality in Blacks than Whites has been consistently reported in the US, but previous investigations have not accounted for poverty at the individual level. The health of its population is an important part of the capital of a nation. We examined the association between individual level poverty and disability and racial mortality differences in a 5% Medicare beneficiary random sample from 2004 to 2010. Cox regression models examined associations of race with all-cause mortality, adjusted for demographics, comorbidities, disability, neighborhood income, and Medicare "Buy-in" status (a proxy for individual level poverty) in 1,190,510 Black and White beneficiaries between 65 and 99 years old as of January 1, 2014, who had full and primary Medicare Part A and B coverage in 2004, and lived in one of the 50 states or Washington DC. Overall, black beneficiaries had higher sex-and-age adjusted mortality than Whites (hazard ratio [HR] 1.18). Controlling for health-related measures and disability reduced the HR for Black beneficiaries to 1.03. Adding "Buy-in" as an individual level covariate lowered the HR for Black beneficiaries to 0.92. Neither of the residential measures added to the predictive model. We conclude that poorer health status, excess disability, and most importantly, greater poverty among Black beneficiaries accounts for racial mortality differences in the aged US Medicare population. Poverty fosters social and health inequalities, including mortality disparities, notwithstanding national health insurance for the US elderly. Controlling for individual level poverty, in contrast to the common use of area level poverty in previous analyses, accounts for the White survival advantage in Medicare beneficiaries, and should be a covariate in analyses of administrative databases.
Keywords: Buy-in; Dual-eligible; Medicaid; Medicare; USA; USRDS; disability; disparities; mortality; neighborhood; poverty; race; socioeconomic status.