Medicare's race, ethnic data often undercounts minority populations, study finds

The information critical to a nationwide priority of reducing health care disparities among minorities is incomplete and inaccurate, according to a new Rutgers study.

Published in Medical Care Research & Review and Medical Care, the study compared Medicare beneficiaries' race and ethnicity data from the two most widely-used administrative data sources, to data sources that include beneficiaries' self-reported race and ethnicity information and found that in 19 states the administrative data sources significantly undercount the proportion of people who are Hispanic. It discovered even more widespread undercounting of Asian American, Native Hawaiian, Pacific Islander, and American Indian populations.

The study was led by Olga Jarrín Montaner, assistant professor at Rutgers School of Nursing and Institute for Health, Health Care Policy, and Aging Research and Irina Grafova, assistant professor at Rutgers School of Public Health.

Since the United States' population of older adults is not only just rapidly growing but also becoming more racially and ethnically diverse, collecting and using accurate data on this population's race and ethnicity is needed to identify disparities in health care access and quality of care and is vital for identifying systemic barriers to improving minority health outcomes.

"The inaccuracy of state-level data on Medicare beneficiaries' race and ethnicity is staggering," said Grafova. "We found that, in 19 states, about 20 percent of Hispanic Medicare beneficiaries were misclassified as belonging to another ethnic group. In 24 states, more than 80 percent of American and Alaskan Native beneficiaries of Medicare were misclassified. And in the majority of states, at least one-fourth of Asian American and Pacific Islander beneficiaries were misclassified."

Medicare requires the collection of self-reported race and ethnicity data during standardized assessments in home health care and other care settings and should be used whenever possible by researchers who are documenting racial disparities and the impact of racism on healthcare use and outcomes, Jarrin said.

"The Centers for Medicare and Medicaid can incorporate our findings to improve the accuracy of racial and ethnic data used in the future to estimate minority health and health disparities within the U.S. Medicare population," she said. "By creating more accurate estimates of the demographic profile of older adults, we can inform future public health and policy, and better understand the magnitude of disparities in population health outcomes, such as those we are currently seeing with COVID-19,"