Health insurance premiums for Hawaii Medical Serv­ice Association’s small- business plans rose an average 7 percent in July for roughly 50,000 members.

The rate hike affecting 5,400 small businesses compares with an average 2.1 percent increase a year ago.

“The best way to keep health care affordable is to improve the health of our members at small businesses and across Hawaii,” HMSA spokeswoman Elisa Yadao said in a statement. “We provide high quality benefits for preventive care that keep people healthy and give our members convenient access to the largest network of doctors and hospitals.”

Some small groups could see higher or lower medical and drug premiums than the average approved by the state Insurance Division, which regulates health plan rates, depending on utilization and other factors.

HMSA said it is starting to see efforts to control costs working among its nearly 735,000 members.

The state’s largest health insurer initiated a controversial payment model in recent years, reimbursing doctors a fixed monthly rate for each patient in a practice, instead of fee-for-service, which reimburses doctors based on the number of patient visits and type of service. It also has started paying for gym memberships and partnered with the Blue Zones Project, which helps improve access to healthful food and exercise in certain communities throughout the state.

“A 7 percent rate increase is not sustainable, so we need to address health care cost drivers to bring the rate increases down to a level that makes it sustainable. The efforts to improve population health must continue,” said Insurance Commissioner Gordon Ito. “We must address the increasing trend of obesity, kidney disease and diabetes, which incur significant health care (costs) for the treatment of these chronic conditions. If we can turn the trend around on population health and prevent people from getting chronic illnesses, we can save significant health care dollars. The importance is improving people’s health.”