New Research Highlights Key Characteristics of New ACOs

Medicare Accountable Care Organizations (ACOs) are now running, but until now we knew little about exactly what types of organizations were participating in the ACO programs.

Arnold Epstein and other researchers compared ACOs with non-ACO providers using publicly available data from the Centers for Medicare and Medicaid Services, the American Hospital Association’s 2011 Annual Survey of Hospitals, the U.S. census, and the Dartmouth Atlas of Health Care.

The median income is estimated (based on the patient’s zip code) to be $61,726 for ACO patients versus $54,939 for non-ACO patients.

Median Income for ACO and No(1)

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87.0% of ACO patients are white, compared with 84.9% of non-ACO patients.

Race of ACO Patients vs Non-(1)

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Percent of Patients Who Are

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In addition, the authors found that ACOs participating in the programs were most heavily concentrated in the South. Below is a map of ACOs:


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ACO patients were more likely to be older than 80, more likely to be white, and more likely to have a higher income than were non-ACO participants. In addition, ACO patients were less likely to be covered by Medicaid or disabled.

ACO patients had 5.8% lower total costs of care than non-ACO patients. ACO patients had an average cost of care of $7,694, whereas non-ACO patients had an average cost of care of $8,164.

Total Cost of Care

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Only 46% of the ACOs had a participating hospital.

Percent of ACOs with a Parti

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In general, hospitals that did participate in ACOs tended to be large, nonprofit teaching hospitals. Researchers found that the quality of care provided by hospitals participating in ACOs was similar to the quality of care found in non-participating hospitals.

Regional healthcare markets containing ACOs tended to have larger populations and have higher Medicare spending per beneficiary. In addition, these regions had more providers (both primary care physicians and specialists) per capita. They also had fewer hospital beds per capita.

Although modest, the differences in socioeconomic characteristics between patients in ACOs and other patients raise concerns about ensuring that people of lower socioeconomic status have equal access with those of higher socioeconomic status to any benefits that ACOs may provide.”—Arnold Epstein et. al.

It will be important to keep an eye on differences in socioeconomic characteristics (as well as quality of care measures) for ACOs versus non-ACOs to ensure that everyone has access to any benefits that ACOs may provide, whether quality of care or cost effectiveness.

Here is an infographic that explains the key differences between Accountable Care Organizations and non-ACOs:


You can embed this infographic in your article or blog post with the following embed code:

<p><img alt="ACO Infographic" src="/blog/wp-content/uploads/2014/01/aco_patients_vs_non_aco_patients_infographic.jpg" />
</p><p>Image Credit: <a href="/blog">Additive Analytics Blog</a></p>


  1. A. M. Epstein, A. K. Jha, J. Orav, D. L. Liebman, A–M. J. Audet , M. A. Zezza, and S. Guterman, “Analysis of Early Accountable Care Organizations Defines Patient, Structural, Cost, and Quality-of-Care Characteristics,” Health Affairs, Jan. 2014 33(1):95–102.

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