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

McConnell K, Renfro S, Chan B, Meath T, Mendelson A, Cohen D, Waxmonsky J, McCartjhy D, Wallace N, Lindrooth R
Publication Year: 2017
Patient Need Addressed: Care Coordination/Management
Population Focus: Medicaid beneficiaries
Intervention Type: Service redesign
Study Design: Pre-post without Comparison Group
Type of Literature: White

A variety of state Medicaid reforms are underway, but the relative performance of different approaches is unclear.

To compare performance in Oregon’s and Colorado’s Medicaid Accountable Care Organization (ACO) models.

Oregon initiated its Medicaid transformation in 2012, supported by a $1.9 billion federal investment, moving the majority of Medicaid enrollees into sixteen Coordinated Care Organizations (CCOs), which managed care within a global budget. Colorado initiated its Medicaid Accountable Care Collaborative (ACC) in 2011, creating seven Regional Care Collaborative Organizations that received funding to coordinate care with providers and connect Medicaid enrollees with community services. We analyzed data spanning July 1, 2010 through December 31, 2014, (18 months pre-intervention and 24 months post intervention, treating 2012 as a transition year) for 452,371 Oregon and 330,511 Colorado Medicaid enrollees, assessing changes in outcomes using difference-in-differences analyses.

Both states emphasized a regional focus, primary care homes, and care coordination. Oregon’s CCO model was more comprehensive in its reform goals and in the imposition of downside financial risk.

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


    Standardized expenditures for selected services declined in both states over the 2010–2014 time period, but these decreases were not significantly different between the two 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, three out of four measures of access, and one out of four measures of appropriateness of care.

    Conclusions and Relevance
    Two years into implementation, Oregon 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 on a number of other metrics.

Insights Results

Cost outcomes

  • Standardized expenditures decreased in Oregon relative to Colorado, but after adjusting for demographic and health risk, there was no significant difference ($2.00; 95% CI [CI] −$0.79 to $4.78) in per member per month standardized expenditures for Oregon’s Medicaid enrollees; positive values indicate higher growth in standardized expenditures in Oregon relative to Colorado
  • In general, performance on standardized expenditures for most measures was similar in the first and second year, with some exceptions. For example, relative to Colorado, standardized expenditures for inpatient services were significantly higher for Oregon in the second year of implementation ($4.37; 95% CI $0.01 to $8.73)
  • Relative to Colorado, Oregon’s growth in overall standardized expenditures was lower for adults, compared to children, but neither group showed statistically significant differences between the states
    Care/quality outcomes
  • Patterns were generally similar across metrics for both children and adults, with some exceptions. For example, decreases in emergency department visits for Oregon relative to Colorado were statistically significant for adults but not children
  • Of note, although primary care utilization decreased across both states, Oregon maintained or improved care in three of four measures of access (well child visits for children ages 3–6: +2.7%, 95% CI 1.2% to 4.2%; adolescent well care visits: +6.8%, 95% CI 5.2% to 8.3%; adult access to preventive ambulatory care: +1.3%, 95% CI 0.3% to 2.2%) relative to Colorado
  • Oregon also improved on measures of avoidable emergency department (ED) visits, decreasing by 1.8 per 1,000 member months (95% CI −3.1 to −0.4), as well as acute PQI preventable hospitalizations (−1.0 per 1000 member months, 95% CI −1.6 to −0.4)
  • Relative to Colorado, Oregon’s coordinated care organization (CCO) transformation was not associated with statistically significant improvements in three out of four measures of low-value care. However, avoidance of imaging for uncomplicated headache improved by 2.6% relative to Colorado (95% CI 1.4% to 3.8%)
  • Unlike the Oregon CCO model, the accountable care collaborative (ACC) model maintained fee-for-service payments and did not impose downside financial risk on providers or regional care collaborative organization (RCCOs). Furthermore, Colorado did not receive federal investments on the scale of those provided to Oregon
  • Oregon’s reduction in primary care visits was accompanied by relative or absolute improvements in most HEDIS access measures, suggesting the potential for a more efficient reconfiguration of primary care resulting in fewer visits but maintaining access