A 5 minute read
doctors around a table discussing
September 19, 2017

*Updated as of May 6, 2019.

The Centers for Medicare and Medicaid Services (CMS) is putting increasing pressure on healthcare providers to deliver high-quality care to patients at the lowest possible cost while simultaneously reducing preventable readmissions. Some care providers have joined accountable care organizations (ACOs) to meet these expectations. Though ACOs can provide coordinated, timely care, they have limitations as a group of voluntarily affiliated individual providers, care centers, and health plans.

Integrated delivery networks (IDNs) are similar to ACOs in that they are systems of providers and care sites that aim to improve patient experience and care outcomes while reducing cost. Unlike an ACO, a healthcare IDN is a cohesive health system that offers a full range of preventative and acute care services as well as health insurance plans, rather than a loose collection of individual providers and payors. IDNs are one of the most common hospital affiliations. Definitive Healthcare currently tracks nearly 1,700 ACOs and more than 980 IDNs across the United States.

Top 10 ACOs by Patient Population

Rank ACO Name Patient Population
 1.   TMA PracticeEdge (Texas Medical Association - Blue Cross and Blue Shield of Texas ACO)  5,000,000 
2.   Aetna - Childrens Hospital of Philadelphia (CHOP) ACO 1,400,000 
3.   Steward Integrated Care Network (AKA Steward Promise) 1,000,000 
4.   Aetna - Carilion Clinic ACO 1,000,000 
5.   Capital Bluecross - Heritage Medical Group ACO 700,000 
6.   Anthem Blue Cross of California - Healthcare Partners ACO 675,000 
7.   Aetna - Riverside Health System ACO 500,000 
8.   Horizon Blue Cross Blue Shield of New Jersey - Partners in Care ACO 500,000 
9.   Aetna - Virtual Medical Group ACO 400,000 
10.   Advocatecare ACO 375,000 

Fig 1 Data from Definitive Healthcare's connected care platform, which includes intelligence on ACOs, HIEs, and payors.

In order to improve on hospital performance metrics, such as quality scores and clinical outcomes, both IDNs and ACOs must monitor patient population health. As regional organizations, IDNs are in a unique position to assess the particular needs of the local population. These insights allow IDNs to focus on the most prevalent health issues in their communities, such as diabetes, asthma, or other chronic conditions.

IDNs, in particular, are able to address social determinants of health due to their holistic approach to patient health. Because many IDNs own or manage specialty and home care services, they can respond quickly to urgent patient needs and send paramedics or nurses to patients’ homes for treatment of mental health or substance abuse issues.

Texas alone has 81 IDNs, according to Definitive Healthcare’s hospitals and IDNs platform, and each of these would likely focus on distinct population health needs. Austin, for example, would likely have a younger population and emphasize healthcare that targets mental health and preventative medicine. In a more rural area, where patient populations are likely to be older, healthcare focus might be on diabetes, obesity, and chronic pain management.

For IDNs and ACOs to be successful in delivering quality and cost-effective care, they must utilize convenient and comprehensive data sharing. Some IDNs are beginning to assume risk in terms of bundled payments and population health management. In order to assess this risk, IDNs rely on all-payor claims data through health information systems (HIEs).

For both ACOs and IDNs, HIEs are integral in sharing patient data across the care continuum, allowing providers to coordinate care and ensure that there are no gaps in treatment. These organizations can also engage providers by sharing data on key metrics, like readmission rates and length of stay, as well as feedback on their own patients in terms of experience and overall health.

Another incentive for being part of a coordinated care organization is the ability to reduce care costs for patients and care providers. Where ACOs themselves cannot be part of group purchasing organizations (GPOs), their member hospitals often are. Approximately 76 percent of IDNs are affiliated with at least one GPO, according to Definitive Healthcare data, with the most popular being Vizient. However, IDNs can also leverage their size to negotiate prices on their own without GPO affiliation.


Purchasing is one of many benefits of membership, which is convenient for the 75 percent of hospitals affiliated with an IDN. In comparison, only about 34 percent of hospitals are part of both an ACO and a GPO.

One of the largest healthcare costs is for employers providing employee health benefits. Many employers cannot afford to use traditional channels to offer health insurance, and some are turning to regional IDNs. Because IDNs can offer their own health plans, they are increasingly attractive to employers requiring employee benefit plans. Both ACOs and IDNs are being asked by employers to take on greater risks for managing employee health through bundled payments and networks. This puts both types of organizations in a unique place in terms of coordinating affordable care while simultaneously reducing purchasing costs.

Healthcare IDNs are in a pivotal place on the healthcare continuum. They can offer their own healthcare plans while managing and operating their own primary, specialty, and acute care centers and physicians. Because IDNs control every aspect of their networks, it is easier to reap the benefits of group purchasing, direct contracts with employers, and data sharing through HIEs. These factors suggest that IDNs could be able to shape healthcare practices and trends moving forward

Looking for more information? Definitive Healthcare tracks nearly 8,900 hospitals & IDNs, more than 60 GPOs, roughly 1,700 ACOs, and dozens of other healthcare organizations in one comprehensive platform. Our in-house research tea, gathers and verifies affiliations intelligence, with updates added every day.

To learn more about how Definitive Healthcare’s platform could benefit your business, sign up for a free trial today!

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