Emory Healthcare and Aetna are teaming up in a collaboration known as an “accountable care organization’’ (ACO), which aims to enhance patient care and reduce costs.

ACOs are networks of hospitals and doctors — and sometimes insurers — that arose as a central feature of the 2010 Affordable Care Act.

Medical providers in ACOs typically are rewarded based on the quality of care they provide. Under a special Medicare program, the organizations get paid more for keeping their patients healthy and out of the hospital. Several ACOs have been formed in Georgia.

The ACO announcement Thursday did not mention Emory’s potential merger with rival WellStar Health System, nor what role the Aetna ACO might have in a merged entity.

Emory and WellStar, both major players in the metro Atlanta market, are currently in talks to merge their health care assets into a new medical powerhouse.

Janet Christenbury, a spokeswoman, said Emory cannot speculate about the Aetna collaboration in relationship to the WellStar talks.

Connecticut-based Aetna has about 700,000 members in Georgia, while Emory Healthcare is the largest health system in Georgia.

Emory  and Aetna have worked together on a “patient-centered medical home” arrangement since 2011.

A year ago, Emory announced an ACO with Blue Cross and Blue Shield of Georgia, the state’s leading insurer, to target employers. Aetna, meanwhile, has ACOs in several markets nationally.

A goal of such collaborations is to coordinate care for patients, especially those with chronic health conditions.

Emory and Aetna will have joint responsibility for quality of care, patient satisfaction and costs related to the services they provide.

“We are very excited about our new collaboration with Emory Healthcare,”  Angela Meoli, president of Aetna’s operations in Georgia, Louisiana, Alabama and Mississippi, said in a statement. “Working with health systems like Emory, we’re redefining the relationship between insurers and providers. The end result will be better, more efficient and more affordable care for our members.”

“This ACO allows us to provide a wide variety of high-quality health care services through a sustainable health care delivery system that offers value to patients, employers and payers by delivering outstanding clinical care and outcomes,” said Patrick Hammond, CEO of the Emory Healthcare Network. “By collaborating on care, the organizations are able to reduce unnecessary repeat services and procedures, as well as their associated costs.”

Nationally, accountable care organizations have shown some promise.

About a quarter of the 243 groups of hospitals and doctors that banded together as accountable care organizations under the Affordable Care Act saved Medicare enough money to earn bonuses, federal officials said in September, according to Kaiser Health News.

Yet three years after Medicare selected 32 ACOs for what it dubbed its Pioneer Program, the number of players dropped to 19 by last September.

Craig Savage, a consultant with North Carolina-based CMBC Advisors, said Thursday that ACOs have not generated enough data to prove their effectiveness. “It’s too early to tell,’’ he said.

“In terms of managing population health, they make a lot of sense to me,’’ Savage added. Key questions for how well an ACO will work, he said, include whether it has enough patients as members and whether it has enough physicians.