Study finds Medicare Advantage networks are broad and getting broader

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.

A new study led by Boston University School of Public Health (BUSPH) researchers finds that networks in Medicare Advantage—a private plan alternative to traditional Medicare—are relatively broad and may be getting broader. The study, published in the April issue of 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.

"This should be good news for folks concerned about insurers excessively restricting access to providers," says lead study author Yevgeniy Feyman, a doctoral student at BUSPH.

Previous studies have suggested that over a third of Medicare Advantage beneficiaries were in narrow networks, but these studies relied on physician directories, which are prone to error. 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. Among plans that were on the market for all five years of the analysis, the researchers found that 64 percent of the plans with narrow networks in 2011 were no longer narrow in 2015, while 99.5 percent of plans with medium or broad networks in 2011 still did 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).