CONCORD — Two groups of medical care providers that serve New Hampshire were among 89 nationally selected to participate in a new federal program aimed at improving health care quality and reducing costs, the Obama administration said Monday.

Concord Elliot ACO LLC, based in Manchester, and Circle Health Alliance LLC, based in Lowell, Mass., are accountable care organizations (ACOs) participating in the government’s Medicare Shared Savings Program, an initiative of President Barack Obama’s Affordable Care Act that was recently ruled constitutional by the Supreme Court.

Concord Elliot comprises 234 physicians and will serve Medicare recipients in New Hampshire, while Circle Health Alliance has 353 physicians and will serve Medicare beneficiaries in Massachusetts as well as New Hampshire. Both groups are in partnerships with area hospitals.

The federal Centers for Medicare and Medicaid Services (CMS), which administers the Medicare program, said participation in an ACO is “purely voluntary for providers.”

The agency said that under its agreements with ACOs, the organizations are “taking responsibility for the quality of care they provide to people with Medicare in return for the opportunity to share in savings realized through high-quality, well-coordinated care.”

The CMS said savings from the initiative “could be up to $940 million over four years.”

U.S. Health and Human Services Secretary Kathleen Sebelius said in a statement, “Better coordinated care is good for patients and it saves money. We applaud every one of these doctors, hospitals, health centers and others for working together to ensure millions of people with Medicare get better, more patient-centered, coordinated care.”

The CMS said the Medicare Shared Savings Program was created by the Affordable Care Act. It said the program is intended to encourage physicians and other providers of Medicare-covered services and supplies, such as hospitals and others involved in patient care, to create ACOs and “agree to be held accountable for improving the health and experience of care for individuals and improving the health of populations, while reducing the rate of growth in health care spending.

“Studies have shown that better care often costs less, because coordinated care helps to ensure that the patient receives the right care at the right time, partly because patients avoid unnecessary duplication of services and dangerous medical errors,” CMS said.

The 89 ACOs announced Monday bring to 154 the total number of ACOs participating in the shared savings program, CMS said. It said that more than 2.4 million Medicare beneficiaries are now receiving care from such providers in 40 states and Washington.

Jonathan Blum, principal deputy administrator of CMS, said the number of participating ACOs “exceeds our goals that we had for the year.”

In New Hampshire, Dartmouth Health Care announced in December 2011 that it was one of 32 health providers joining Medicare’s Pioneer Accountable Care Organization model.

Participating ACOs must meet quality standards. The CMS has established 33 measures related to “care coordination and patient safety, appropriate use of preventive health services, improved care for at-risk populations, and patient and caregiver experience of care.”