Effects of Medicare eligibility and enrollment at age 65 among immigrants and US ‐born residents

Understanding the impacts of Medicare coverage among immigrants is of high policy importance, but there is currently limited evidence. In this study, we examined the effects of near universal access to Medicare coverage at age 65 years between immigrants and US-born residents.Using the 2007-2019 Medical Expenditure Panel Survey, we employed a regression discontinuity design, which exploits the eligibility for Medicare at age 65 years. Our outcomes were health insurance coverage, healthcare spending, access to and use of health care, and self-reported health status.Medicare eligibility at age 65 led to significant increases in Medicare coverage among immigrants and US-born residents (74.6 [95% CI: 71.6-77.5] and 81.6 [95% CI: 80.5-82.7] percentage points). Medicare enrollment at age 65 decreased total healthcare spending and out-of-pocket spending by $1579 (95% CI: -2092 to 1065) and $423 (95% CI: -544 to 303) for immigrants and $1186 (95% CI: -2359 to 13) and $450 (95% CI: -774 to 127) for US-born residents. After Medicare enrollment at age 65, immigrants reported only limited improvements in overall access to and use of health care, but they reported significant increases in the use of high-value care (11.5 [95% CI: 6.8-16.2], 8.3 [95% CI: 6.0-10.6], 8.4 [95% CI: 1.0-15.8], and 2.3 [95% CI: 0.9-3.7] percentage points increase for colorectal cancer screening, eye examination for diabetes, influenza vaccine, and cholesterol measurement) and improvements in self-reported health (5.9 [95% CI: 0.9-10.8] and 4.8 [95% CI: 0.5-9.0] percentage points increase for good perceived physical and mental health). Medicare enrollment also increased prescription drug spending by $705 (95% CI: 292-1117), despite the unchanged use of prescription drugs. For US-born residents, use of high-value care, self-reported health, and prescription drug use and spending did not change substantially after Medicare enrollment.Medicare has the potential to improve care among older adult immigrants.