Top 25 Accountable Care Organizations by Patient Population

An Accountable Care Organization (ACO) is a formal group of physicians, hospitals, or other care providers that voluntarily work together to deliver high-quality coordinated care to Medicare beneficiaries. The goal of an ACO is to provide affordable care through reducing or eliminating unnecessary duplication of tests or services, lowering the risk of medical errors. For each ACO, there is a defined patient population, primarily composed of Medicare beneficiaries, for which it is held accountable in terms of care cost, gross savings, and quality.

The following list highlights the top 25 ACOs by patient population, representing over 15.7 million patients with an average population of 628,000. Of the top 25, 92 percent are classified as commercial ACOs— an ACO model with a non-government payer.

TMA PracticeEdge, a commercial ACO based out of Austin, TX, ranks first with a patient population of five million — 112-percent higher than the next highest ACO, Aetna-Children’s Hospital of Philadelphia (CHOP) which has a patient population of 1.4 million.

Top 25 Accountable Care Organizations by Patient Population

Rank	Definitive ID	ACO Name	ACO Type	City	State	ACO Start Date	Patient Population
1	810909	TMA PracticeEdge (Texas Medical Association - Blue Cross and Blue Shield of Texas ACO)	Commercial ACO	Austin	TX	2015 Q1	5,000,000
2	842940	Aetna - Childrens Hospital of Philadelphia (CHOP) ACO	Commercial ACO	Philadelphia	PA	2015 Q4	1,400,000
3	552096	Steward Integrated Care Network	Medicare Next Generation ACO	Needham	MA	2016 Q1	1,000,000
3	552289	Aetna - Carilion Clinic ACO	Commercial ACO	Roanoke	VA	2011 Q3	1,000,000
5	552388	Capital Bluecross - Heritage Medical Group ACO	Commercial ACO	Lemoyne	PA	2011 Q2	700,000
6	579844	Anthem Blue Cross of California - Healthcare Partners ACO	Commercial ACO	Torrance	CA	2013 Q4	675,000
7	579912	Aetna - Riverside Health System ACO	Commercial ACO	Newport News	VA	2013 Q2	500,000
7	585269	Horizon Blue Cross Blue Shield of New Jersey - Partners in Care ACO	Commercial ACO	East Brunswick	NJ	2014 Q1	500,000
9	823406	Aetna - Virtual Medical Group ACO	Commercial ACO	Marlton	NJ	2015 Q1	400,000
10	552285	Advocatecare ACO	Commercial ACO	Chicago	IL	2011 Q1	375,000
10	969400	BCBS Illinois - Advocate Physician Partners Accountable Care	Commercial ACO	Rolling Meadows	IL	2012 Q3	375,000
12	969315	BCBS Arizona - Banner Health Network ACO	Commercial ACO	Phoenix	AZ	2012 Q1	350,000
12	553402	Cigna - Banner Health Network ACO	Commercial ACO	Phoenix	AZ	2012 Q4	350,000
14	577487	UnitedHealthcare - Seton Health Alliance ACO	Commercial ACO	Austin	TX	2013 Q3	320,000
15	578002	Partners for Kids ACO	Medicaid ACO	Columbus	OH	2012 Q3	300,000
15	969460	HealthPartners - Northwest Metro Alliance	Commercial ACO	Bloomington	MN	2010 Q1	300,000
17	585460	Blue Shield of California - EPIC ACO	Commercial ACO	Redlands	CA	2014 Q1	273,000
18	835846	University Hospitals - Anthem Blue Cross and Blue Shield ACO	Commercial ACO	Cleveland	OH	2015 Q3	270,000
19	849729	Humana - DeKalb PHO ACO	Commercial ACO	Decatur	GA	2016 Q1	250,000
19	858080	DeKalb Medical Physicians Group - UnitedHealthcare ACO	Commercial ACO	Decatur	GA	2016 Q3	250,000
19	947978	Cigna - DeKalb Physicians Health Organization	Commercial ACO	Decatur	GA	2015 Q4	250,000
22	552351	Cigna - Westmed Medical Group ACO	Commercial ACO	Purchase	NY	2012 Q2	237,000
23	553396	OptumCare - North American Medical Management California ACO	Commercial ACO	Ontario	CA	2012 Q4	229,000
24	574791	Rainbow Care Connection	Commercial ACO	Cleveland	OH	2012 Q3	200,000
24	777076	Health Choice Utah	Medicaid ACO	South Jordan	UT	2013 Q1	200,000

Fig 1.  Data from Definitive Healthcare from the Accountable Care Organizations Database. Data is from the Center for Medicare & Medicaid Services and Definitive Healthcare proprietary data. Most recent data available, accessed in April 2020.