Faced with this new reality, "insurers turned to limiting the number of providers covered within plans," the researchers reported. "The analysis … found that while provider networks did not change significantly for small group plans, this was a routine practice in the individual insurance marketplaces. Some raised concerns about patients' limited access to care, but the states studied have not received complaints from consumers, who by and large were willing to forgo greater access to more providers for lower premiums."

 Among the findings from the research:

• Officials in all six states report an expectation that carriers will narrow networks even further in 2015;
• Though carriers implemented changes to their individual market plans both inside and outside the marketplaces, they made fewer changes to their offerings to small businesses;
• Carriers generally didn't report any efforts to design a network built on providers' performance on quality metrics or patient outcomes; price was the determining factor for whether a provider was included or excluded from most networks;
• Carriers in New York and Oregon reported an interest in maintaining narrower, "more tightly managed" networks in order to promote a patient-centered medical home delivery model;

• State officials and carriers reported that consumers were generally not complaining about difficulty obtaining needed care from providers. Consequently, most state legislatures, officials and regulators are unlikely to change network adequacy standards, at least in the short-term;
• Network design strategies differed between regions within states, with carriers almost universally reporting that attempting to achieve lower premiums through a "narrow" network strategy was really only possible in large urban markets with a robust supply of providers;
• Carriers operating in rural areas reported less competition among carriers than in urban areas; thus, they had less incentive to lower premiums to attract price-conscious consumers;
• Other insurers shifted from offering both PPO (preferred provider organization) and HMO (health maintenance organization) plan offerings to only HMO offerings for their individual market products, both on and off the marketplace;
• A leading carrier in Colorado screened out high-priced hospital providers and excluded them from the networks of their 2014 plans. Physicians that had been in-network for the insurer but are aligned with out-of-network hospitals are now no longer in-network.

The report called out the strategies carriers deployed in New York to try to keep premiums at competitive rates.

"Some [New York] insurers reduced the number of network providers relative to their off-marketplace plans; others entered into an exclusive or semi-exclusive alignment with a particular hospital system," the report said. "New York insurers also shifted away from PPO-style plans that offer an out-of-network benefit.

"One marketplace official told us, 'there were virtually no out-of-network products in the individual market [for 2014].' This was in part because of a marketplace requirement that insurers offering an out-of-network benefit outside of the marketplace also offer an out-of-network benefit inside the marketplace. Rather than comply with this requirement, most individual market insurers decided not to offer out-of-network benefits anywhere."