"These innovative programs are showing encouraging initial results, while providing valuable lessons as we strive to improve our nation's health-care delivery systems," said Health and Human Services Secretary Kathleen Sebelius, whose department oversees CMS.
Montefiore Medical Center in the Bronx section of New York City, recorded the best financial performance of the Pioneer ACOs, with a 7 percent reduction of costs. That led to $23 million in savings to Medicare, of which Montefiore retained $14 million.
Montefiore Vice President of Network Management, Stephen Rosenthal, said the ACO "model allows us to be proactive, to avoid unnecessary costs from occurring." Because of the Bronx's status as one of the poorest areas of the United States, "many of these interventions are focused not only on health problems, but also on behavioral problems."
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Rosenthal cited the example of a patient named John, a Bronx taxi driver, whose diabetes had been out of control as a result of his job schedule and other factors, leading to 42 separate emergency room admissions in a single year.
The ACO intervened in John's treatment, and assigned a diabetes educator to him. In the year when he was actively being monitored by the ACO, Rosenthal said, John went to the ER just once.
Meghan FitzGerald, president of Cardinal Health Specialty Solutions, who also teaches a class in "Business of Healthcare" at Columbia University, said Montefiore and the other providers involved in ACOs "represent a larger movement towards value in health care."
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"Some of the best results are seen when all stakeholders—physicians, payers and patients are engaged and incentives are aligned," FitzGerald told CNBC.com. "Working with these groups together was once considered unheard of but in a new era of health care, eliminating waste and promoting appropriate care are a result of 360-degree partnership, which has been helped by public-company innovation and technology."
—By CNBC's Dan Mangan. Follow him on Twitter