Early Performance in Medicaid Accountable Care Organizations: A Comparison of Oregon and Colorado

JAMA Intern Med. 2017 Apr 1;177(4):538-545. doi: 10.1001/jamainternmed.2016.9098.


Importance: Several state Medicaid reforms are under way, but the relative performance of different approaches is unclear.

Objective: To compare the performance of Oregon's and Colorado's Medicaid Accountable Care Organization (ACO) models.

Design, setting, and participants: Oregon initiated its Medicaid transformation in 2012, supported by a $1.9 billion investment from the federal government, moving most Medicaid enrollees into 16 Coordinated Care Organizations, which managed care within a global budget. Colorado initiated its Medicaid Accountable Care Collaborative in 2011, creating 7 Regional Care Collaborative Organizations that received funding to coordinate care with providers and connect Medicaid enrollees with community services. Data spanning July 1, 2010, through December 31, 2014 (18 months before intervention and 24 months after intervention, treating 2012 as a transition year) were analyzed for 452 371 Oregon and 330 511 Colorado Medicaid enrollees, assessing changes in outcomes using difference-in-differences analyses of regional focus, primary care homes, and care coordination. Oregon's Coordinated Care Organization model was more comprehensive in its reform goals and in the imposition of downside financial risk.

Exposures: Regional focus, primary care homes, and care coordination in Medicaid ACOs.

Main outcomes and measures: Performance on claims-based measures of standardized expenditures and utilization for selected services, access, preventable hospitalizations, and appropriateness of care.

Results: In a total of 782 882 Medicaid enrollees, 45.0% were male, with mean (SD) age 16.74 (14.41) years. Standardized expenditures for selected services declined in both states during the 2010-2014 period, but these decreases were not significantly different between the 2 states. Oregon's model was associated with reductions in emergency department visits (-6.28 per 1000 beneficiary-months; 95% CI, -10.51 to -2.05) and primary care visits (-15.09 visits per 1000 beneficiary-months; 95% CI, -26.57 to -3.61), improvements in acute preventable hospital admissions (-1.01 admissions per 1000 beneficiary-months; 95% CI, -1.61 to -0.42), 3 of 4 measures of access (well-child visits, ages 3-6 years, 2.69%; 95% CI, 1.20% to 4.19%; adolescent well-care visits, 6.77%; 95% CI, 5.22% to 8.32%; and adult access to preventive ambulatory care, 1.26%; 95% CI, 0.28% to 2.25%), and 1 of 4 measures of appropriateness of care (avoidance of head imaging for uncomplicated headache, 2.59%; 95% CI, 1.35% to 3.83%).

Conclusions and relevance: Two years into implementation, Oregon's and Colorado's Medicaid ACO models exhibited similar performance on standardized expenditures for selected services. Oregon's model, marked by a large federal investment and movement to global budgets, was associated with improvements in some measures of utilization, access, and quality, but Colorado's model paralleled Oregon's on several other metrics.

Publication types

  • Comparative Study

MeSH terms

  • Accountable Care Organizations* / economics
  • Accountable Care Organizations* / standards
  • Adolescent
  • Adult
  • Child
  • Colorado
  • Efficiency, Organizational
  • Female
  • Financing, Government / methods
  • Health Expenditures / statistics & numerical data
  • Health Services* / economics
  • Health Services* / statistics & numerical data
  • Humans
  • Male
  • Managed Care Programs* / economics
  • Managed Care Programs* / organization & administration
  • Medicaid* / economics
  • Medicaid* / organization & administration
  • Models, Organizational
  • Oregon
  • Quality Improvement
  • Regional Health Planning
  • United States