Changes in Racial and Ethnic Disparities in Access to Care and Health Among US Adults at Age 65 Years

Abstract

Importance: Medicare provides nearly universal health insurance to individuals at age 65 years. How eligibility for Medicare affects racial and ethnic disparities in access to care and health is poorly understood.

Objective: To assess the association of Medicare with racial and ethnic disparities in access to care and health.

Design, setting, and participants: This cross-sectional study uses regression discontinuity to compare racial and ethnic disparities before and after age 65 years, the age at which US adults are eligible for Medicare. There are a total of 2 434 320 respondents in the Behavioral Risk Factor Surveillance System and 44 587 state-age-year observations in the US Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research Data (eg, the mortality rate for individuals age 63 years in New York in 2017) from January 2008 to December 2018. The data were analyzed between February and May 2021.

Exposures: Eligibility for Medicare at age 65 years.

Main outcomes and measures: Proportions of respondents with health insurance, as well as self-reported health and mortality. To examine access, whether respondents had a usual source of care, encountered cost-related barriers to care, or received influenza vaccines was assessed.

Results: Of 2 434 320 participants, 192 346 were Black individuals, 104 294 were Hispanic individuals, and 892 177 were men. Immediately after age 65 years, insurance coverage increased more for Black respondents (from 86.3% to 95.8% or 9.5 percentage points; 95% CI, 7.6-11.4) and Hispanic respondents (from 77.4% to 91.3% or 13.9 percentage points; 95% CI, 12.0-15.8) than White respondents (from 92.0% to 98.5% or 6.5 percentage points; 95% CI, 6.1-7.0). This was associated with a 53% reduction compared with the size of the disparity between White and Black individuals before age 65 years (5.7% to 2.7% or 3.0 percentage points; 95% CI, 0.9-5.1; P = .003) and a 51% reduction compared with the size of the disparity between White and Hispanic individuals before age 65 years (14.6% to 7.2% or 7.4 percentage points; 95% CI, 5.3-9.5; P < .001). Medicare eligibility was associated with narrowed disparities between White and Hispanic individuals in access to care, lowering disparities in access to a usual source of care from 10.5% to 7.5% (P = .05), cost-related barriers to care from 11.4% to 6.9% (P < .001), and influenza vaccination rates from 8.1% to 3.3% (P = .01). For disparities between White and Black individuals, access to a usual source of care before and after age 65 years was not significantly different: 1.2% to 0.0% (P = .24), cost-related barriers to care from 5.8% to 4.3% (P = .22), and influenza vaccinations from 11.0% to 10.3% (P = .60). The share of people in poor self-reported health decreased by 3.8 percentage points for Hispanic respondents, 2.6 percentage points for Black respondents, and 0.2 percentage points for White respondents. Mortality-related disparities at age 65 years were unchanged. Medicare's association with reduced disparities largely persisted after the US Affordable Care Act took effect in 2014.

Conclusions and relevance: In this cross-sectional study that uses a regression discontinuity design, eligibility for Medicare at age 65 years was associated with marked reductions in racial and ethnic disparities in insurance coverage, access to care, and self-reported health.

Figure 1.. Medicare Eligibility Age-Related Discontinuities in Coverage, Access, and Health by Race and Ethnicity

For each panel, the share of the population that reported an outcome is plotted by age in years separately for White, Black, and Hispanic respondents for the study period (2008-2017). For illustrative purposes, the local linear line of best fit based on the optimal bandwidth selected for our regression discontinuity model is plotted for each racial and ethnic group. The White group is comprised of non-Hispanic, White individuals. The black vertical dotted line denotes the Medicare eligibility age threshold at 65 years. Scatter plots for covariates that should not change but exhibit large changes because of entry to Medicare are presented in eFigure 2 in the Supplement.

Figure 2.. Changes in Racial and Ethnic Disparities in Health Insurance Rates at the Medicare Eligibility Age by Region

The left panel plots the size (and confidence intervals) of the immediate reduction in uninsurance rates (ie, the adjusted discontinuity) at the national level and separately by census regions for each racial and ethnic group. In the right panel, regression discontinuity estimates the adjusted disparities for individuals age 65 years right before Medicare eligibility (in solid) and right after Medicare eligibility (in hollow). The black vertical dotted line is the 0 disparity line; to the left a comparison of the mean outcome for White respondents and racial and ethnic minority respondents indicates that White respondents were better off. ^aAdjusted discontinuity in the disparity (the difference between the 2 points) is statistically significant at the 5% level.

Figure 3.. Changes in Racial and Ethnic Disparities in Coverage, Access, and Health Around the Medicare Eligibility Age Pre-ACA vs Post-ACA

For each outcome, regression discontinuity estimates the adjusted disparities for individuals age 65 years right before Medicare eligibility (in solid triangles) and right after Medicare eligibility (in open triangles) before and after the implementation of the US Affordable Care Act (ACA). The black vertical dotted line is the 0 disparity line; to the left a comparison of the mean outcome for White respondents and racial and ethnic minority groups indicates that White respondents are better off. Panel A shows how the disparity between White and Black respondents changes at age 65 years; panel B shows how the disparity between White and Hispanic respondents changed at age 65 years; and pp indicates percentage points. ^aAdjusted discontinuity in the disparity (the difference between the 2 points) is statistically significant at the 5% level.