Medicare Advantage Networks Are Broad and Getting Broader.

Medicare Advantage—a private plan alternative to traditional Medicare—is growing. In 2017, 33 percent of Medicare beneficiaries were enrolled in Medicare Advantage, up from 22 percent in 2008. Some policymakers have raised concerns that Medicare Advantage networks may have become excessively narrow, making it harder for an enrollee to find a doctor covered by their plan, but little is known about the breadth of these networks and how they may be changing.

It turns out that Medicare Advantage networks are actually relatively broad and may be getting broader, according to a new study led by School of Public Health researchers.

The study, published in Health Affairs, found that the share of Medicare Advantage plans with broad networks increased from 80.1 percent in 2011 to 82.5 percent in 2015, and enrollment in broad-network plans grew from 54.1 percent to 64.9 percent over the same period. Narrow networks were associated with urban areas, higher average income, and having more physicians nearby, as well as more competition between plans.

“We haven’t found evidence that primary care networks in Medicare Advantage are particularly restrictive. This should be good news for folks concerned about insurers excessively restricting access to providers,” says lead study author Yevgeniy Feyman, a doctoral student in the Department of Health Law, Policy & Management.

Previous research has suggested that over a third of Medicare Advantage beneficiaries were in narrow networks, but these studies have relied on physician directories, which are prone to error, and only looked at brief periods.

For this study, supported by the Commonwealth Fund, the researchers instead used Medicare prescription claims data from 2011 through 2015 to infer networks of primary care physicians based on prescription patterns. Using this approach, they were able to look at about half of all Medicare Advantage local Coordinated Care Plan enrollment in the country.

The researchers found that narrow network plans dropped from 2.7 percent of all Medicare Advantage plans in 2011 to 1.8 percent in 2015. When the researchers controlled for demographic factors, they found that the proportion of broad-network plans in rural areas held at around 85 percent, and in urban areas grew from 76 percent to 79 percent.

The broadening of networks was not just due to people switching from narrower plans to broader ones, the researchers found. Among plans that were on the market for all five years of the analysis, the researchers found that 64 percent of the plans that had narrow networks in 2011 were no longer narrow in 2015, while 99.5 percent of plans with medium or broad networks in 2011 still had medium or broad networks in 2015.

The researchers also found that health maintenance organizations (HMOs) had narrower networks than point-of-service (POS) plans and preferred provider organizations (PPOs).

“While we didn’t find evidence that networks are excessively restrictive, that doesn’t mean that that moderate level of restriction is ‘worth it’,” Feyman says. “We still don’t know what sorts of tradeoffs (if any) narrow networks offer, like lower premiums or cost-sharing.”

The new approach used in this study may help regulators to validate provider networks submitted by Medicare Advantage insurers, the authors wrote.

The study was co-authored by Austin Frakt, associate professor of health law, policy & management. The other co-authors were José Figueroa of Harvard Medical School, Daniel Polsky of the University of Pennsylvania, and Michael Adelberg of Faegre Baker Daniels Consulting in Washington, DC.

—Michelle Samuels