Journal of General Internal Medicine

, Volume 34, Issue 7, pp 1116–1118 | Cite as

ACOs and the 1%: Changes in Spending Among High-Cost Patients Following the Medicare Shared Savings Program

  • Adam A. Markovitz
  • Samyukta Mullangi
  • John M. Hollingsworth
  • Ushapoorna Nuliyalu
  • Andrew M. RyanEmail author
Concise Research Reports


Accountable Care Organizations (ACOs) were created by the Centers for Medicare and Medicaid Services (CMS) to improve efficiency and reduce unwarranted regional variations in spending. Because a small subset of high-cost patients drive total Medicare spending and may drive spending variation within and across regions,1 reducing spending among these patients is critical. Studies suggest the Medicare Shared Savings Program—CMS’ flagship ACO program—is associated with modest spending decreases.2, 3 However, it is unknown whether the MSSP has reduced spending for high-cost patients, and, if so, whether this has reduced regional spending variation. We asked two research questions: First, has the MSSP reduced spending for high-cost beneficiaries who potentially drive regional spending variation? Second, has the MSSP reduced spending variation within regions overall?


Using national 100% data for Medicare fee-for-service beneficiaries in 2010 (n = 29,987,387) and 2014 (n =...



This work was supported by the Horowitz Foundation for Social Policy (AAM), AHRQ R36 HS025615 (AAM), AHRQ R01HS024525 (JMH), R01HS024728 (JMH), and NIA R01AG047932 (AMR).

Author Contribution

All authors listed have contributed sufficiently to the project to be included as authors, and all those who are qualified to be authors are listed in the author byline.

Study concept and design: AAM, SM, JMH, AMR

Acquisition, analysis, or interpretation of data: all authors

Drafting of the manuscript: AAM, SM, and ARM

Critical revision of the manuscript for important intellectual content: all authors

Statistical analysis: AAM and UN

Obtained funding: JMH and AMR

Administrative, technical, or material support: JMH and AMR

Compliance with Ethical Standards

This study was exempt from University of Michigan Institutional Review Board oversight.

Conflict of Interest

The authors declare that they do not have a conflict of interest.

Role of the Funder/Sponsor

The funding sources had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.


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Copyright information

© Society of General Internal Medicine 2019

Authors and Affiliations

  • Adam A. Markovitz
    • 1
    • 2
  • Samyukta Mullangi
    • 1
  • John M. Hollingsworth
    • 1
    • 3
  • Ushapoorna Nuliyalu
    • 3
  • Andrew M. Ryan
    • 2
    • 3
    Email author
  1. 1.University of Michigan Medical SchoolAnn ArborUSA
  2. 2.Department of Health Management & Policy University of Michigan School of Public HealthAnn ArborUSA
  3. 3.Institute for Healthcare Policy and InnovationUniversity of MichiganAnn ArborUSA

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