Tufts Health Plan and Steward Health Care System will end their contract for Medicare patients at the end of the year, a move affecting about 10,000 people.

The change applies to people who have primary care doctors in the Steward network and are covered by Tufts’s Medicare Advantage plan. They will have to choose a new doctor to stay in the Tufts plan or choose a new insurance plan if they want to keep their doctors.

“Despite [the] best efforts of both organizations on finding an agreement, we just couldn’t do it,” Tufts spokeswoman Sonya Hagopian said.

Those affected are a small fraction of Tufts’s overall membership of 1.1 million. People covered by other Tufts plans still will have access to the Steward network, Hagopian said.


Steward spokesman Jeff Hall said in a statement that “all patients affected by these changes have been notified directly by both Tufts Health Plan and Steward to let them know of all their available options.”

Tufts and Steward did not explain why they failed to reach an agreement.

Priyanka Dayal McCluskey can be reached at priyanka.mccluskey@globe.com. Follow her on Twitter @priyanka_dayal.