Healthcare Insights
Top 25 Accountable Care Organizations by 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 16.4 million patients with an average population of 657,000. Of the top 25, 84 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
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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 (AKA Steward Promise) |
Medicare Shared Savings 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 |
5 |
552068 |
Atrius Health Pioneer ACO (Closed - Left Pioneer Program) |
Medicare Pioneer ACO |
Newton |
MA |
2012 Q1 |
700,000 |
7 |
579844 |
Anthem Blue Cross of California - Healthcare Partners ACO |
Commercial ACO |
El Segundo |
CA |
2013 Q4 |
675,000 |
8 |
579912 |
Aetna - Riverside Health System ACO |
Commercial ACO |
Newport News |
VA |
2013 Q2 |
500,000 |
8 |
585269 |
Horizon Blue Cross Blue Shield of New Jersey - Partners in Care ACO |
Commercial ACO |
East Brunswick |
NJ |
2014 Q1 |
500,000 |
10 |
823406 |
Aetna - Virtual Medical Group ACO |
Commercial ACO |
Marlton |
NJ |
2015 Q1 |
400,000 |
11 |
552285 |
Advocatecare ACO |
Commercial ACO |
Chicago |
IL |
2011 Q1 |
375,000 |
11 |
969400 |
BCBS Illinois - Advocate Physician Partners Accountable Care |
Commercial ACO |
Rolling Meadows |
IL |
2012 Q3 |
375,000 |
13 |
969315 |
BCBS Arizona - Banner Health Network ACO |
Commercial ACO |
Phoenix |
AZ |
2012 Q1 |
350,000 |
13 |
552349 |
Cigna - Penobscot Community Health Care ACO (Closed) |
Commercial ACO |
Bangor |
ME |
2012 Q2 |
350,000 |
13 |
553402 |
Cigna - Banner Health Network ACO |
Commercial ACO |
Phoenix |
AZ |
2012 Q4 |
350,000 |
16 |
577487 |
UnitedHealthcare - Seton Health Alliance ACO |
Commercial ACO |
Austin |
TX |
2013 Q3 |
320,000 |
17 |
578002 |
Partners for Kids ACO |
Medicaid ACO |
Columbus |
OH |
2012 Q3 |
300,000 |
17 |
552067 |
Allina Health Pioneer ACO (Closed - Left Pioneer Program) |
Medicare Pioneer ACO |
Minneapolis |
MN |
2012 Q1 |
300,000 |
17 |
969460 |
HealthPartners - Northwest Metro Alliance |
Commercial ACO |
Bloomington |
MN |
2010 Q1 |
300,000 |
20 |
585460 |
Blue Shield of California - EPIC ACO |
Commercial ACO |
Redlands |
CA |
2014 Q1 |
273,000 |
21 |
835846 |
University Hospitals - Anthem Blue Cross and Blue Shield ACO |
Commercial ACO |
Cleveland |
OH |
2015 Q3 |
270,000 |
22 |
849729 |
Humana - DeKalb PHO ACO |
Commercial ACO |
Decatur |
GA |
2016 Q1 |
250,000 |
22 |
858080 |
DeKalb Medical Physicians Group - UnitedHealthcare ACO |
Commercial ACO |
Decatur |
GA |
2016 Q3 |
250,000 |
22 |
947978 |
Cigna - DeKalb Physicians Health Organization |
Commercial ACO |
Decatur |
GA |
2015 Q4 |
250,000 |
25 |
552351 |
Cigna - Westmed Medical Group ACO |
Commercial ACO |
Rye Brook |
NY |
2012 Q2 |
237,000 |
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 January 2021.