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Estimating Demand for Care After a Medicaid Expansion: Lessons From Oregon

Gold, Rachel PhD, MPH; Bailey, Steffani R. PhD; O'Malley, Jean P. MPH; Hoopes, Megan J. MPH; Cowburn, Stuart MPH; Marino, Miguel PhD; Heintzman, John MD, MPH; Nelson, Christine PhD, RN; Fortmann, Stephen P. MD; DeVoe, Jennifer E. MD, DPhil

Journal of Ambulatory Care Management: October/December 2014 - Volume 37 - Issue 4 - p 282–292
doi: 10.1097/JAC.0000000000000023
Original Articles

To estimate how the Affordable Care Act's Medicaid expansions will affect demand for services, we measured ambulatory care utilization among adult patients who gained insurance during Oregon's 2008 Medicaid expansion. Using electronic health record data from 67 community health centers, we assessed pre- and postcoverage utilization among patients who gained insurance, compared with patients continuously insured or uninsured. In comparisons of the pre- and postcoverage periods, mean annual encounters among persons who gained insurance increased 22% to 35%, but declined in the comparison groups. These findings suggest that providers should expect a significant increase in demand among patients who gain Medicaid coverage through the Affordable Care Act.

Kaiser Permanente Northwest Center for Health Research, Portland, Oregon (Drs Gold and Fortmann); Oregon Health & Science University, Department of Family Medicine, Portland (Drs Bailey, Marino, Heintzman, and DeVoe); Oregon Health & Science University, Department of Public Health & Preventive Medicine, Division of Biostatistics, Portland (Ms O'Malley); and OCHIN, Inc, Portland, Oregon (Messrs Hoopes and Cowburn and Dr Nelson).

Correspondence: Rachel Gold, PhD, MPH, Kaiser Permanente Northwest Center for Health Research, 3800 N. Interstate Ave, Portland, OR 97227 (

The authors thank the OCHIN practice-based research network health centers.

This study was supported by grant R01HL107647 from the National Heart, Lung, and Blood Institute.

The authors have no conflicts of interest to report.

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