There is little or no competition in Medicare Advantage insurance markets in 97 percent of U.S. counties, including East Baton Rouge and Orleans parishes, according to a new Commonwealth Fund report.

The report, “Competition Among Medicare’s Private Health Plans: Does It Really Exist?,” suggests that lack of competition could create challenges for reforms that rely on competition to improve the efficiency and quality of Medicare Advantage. Only one county, Riverside, California, qualified as a competitive market.

“Allowing private health insurers to play a larger role in Medicare is often suggested as a way to control Medicare costs and improve quality of care,” said Stuart Guterman, senior scholar in residence at AcademyHealth and coauthor of the study. “The idea is if there are more insurers, they’ll fight for customers by lowering premiums and improving quality. For that to happen, however, we need to have enough insurers in a given market — and this study shows that, overwhelmingly, that isn’t the case.”