Looking for Causes of Racial Disparities in Medicare Advantage

By Adrianna McIntyre, PhD, MPP, MPH
May 24, 2022

Adrianna McIntyre is an assistant professor in the Department of Health Policy and Management at the Harvard T.H. Chan School of Public Health. Her research focuses on the politics of health reform and barriers to take-up and retention of social program benefits. Adrianna is a member of the 2022 Tradeoffs Research Council.

Nearly half (45%) of all Medicare enrollees are in private Medicare Advantage (MA) plans. This figure has grown quickly over the past decade, with faster growth among Black, Hispanic and Asian enrollees. But enrollees in these groups are less likely than white enrollees to be in high-quality plans. What might explain this?

In a recent paper in Health Services Research, Sungchul Park, Rachel Werner and Norma Coe looked at one possible explanation: whether the highest quality plans are less likely to be available where minoritized populations live. The authors measured quality using MA’s 5-star ratings.

They found:

  • Black, Hispanic and Asian/Pacific Islander enrollees, on average, had access to a larger number of MA plans than white enrollees, but they were more likely to be choosing from more lower-rated (3.5 stars or fewer) plans and fewer high-rated (ratings 4 stars or higher) plans.

  • Controlling for quality of plans available to enrollees significantly diminished the disparities in enrollment by race and ethnicity: The difference between Black and white enrollees in plans rated 4-4.5 stars almost entirely disappeared, falling from from 9.1 percentage points to 0.5 percentage points. 

  • For Asian/Pacific Islander enrollees the difference in 4-4.5 star enrollment fell by more than two-thirds, from 15.9 percentage points to 5.0 percentage points. 

  • Hispanic enrollees went from being 12.7 percentage points less likely to have a 4-4.5 star plan to 0.6 percentage points more likely.

The study has several limitations. The analytic approach is suggestive, but it doesn’t show that access was the cause of the difference in enrollment patterns. Additionally, the analyses excluded some specialized Medicare populations, so the findings may not generalize to everyone in MA plans. The authors also note that the MA star ratings don’t capture all dimensions of quality.

These findings illuminate another structural barrier to historically marginalized populations accessing high-quality health insurance. The authors suggest the highest rated MA plans might be avoiding markets with large non-white populations that may be more likely to include more people with costly complex health care needs. The researchers argue updating risk adjustment to MA payment rates to account for race and ethnicity directly may help create incentives for a more equitable distribution of high quality MA plans.

Want Research Corner delivered to your inbox every Tuesday? Sign up for our weekly newsletter!