The proposed merger of Aetna and Humana, two of the country’s largest health insurance companies, would reduce competition in Louisiana, already one of the least competitive states in the country.

The findings were part of an American Medical Association analysis of the Aetna-Humana and Anthem-Cigna mergers. The group represents physicians nationwide.

The AMA report says the mergers would reduce competition in up to 154 metropolitan areas within 23 states. The combined impact of the mergers would exceed federal antitrust guidelines in as many as 97 of those metro areas in 17 states. Louisiana’s health insurance market is dominated by Blue Cross and Blue Shield of Louisiana. According to the Kaiser Family Foundation, Blue Cross held more than 60 percent of the large group market and 80 percent of the small group market in 2013. UnitedHealth held the No. 2 spot in large group, with 16 percent of the market. Aetna was third with 10 percent. Humana was No. 2 spot in small group, with 9 percent of the market; and UnitedHealth third, with 7 percent.

“A lack of competition in health insurer markets is not in the best interests of patients or physicians,” said AMA President Dr. Steven J. Stack. “If a health insurer merger is likely to erode competition, employers and patients may be charged higher than competitive premiums, and physicians may be pressured to accept unfair terms that undermine their role as patient advocates and their ability to provide high-quality care.”