Shifting Insurance Landscapes and Access to Care: Insights from Public and Private Insurance Markets

Session Submission Type: Panel

Abstract

As the U.S. healthcare system evolves through consolidation, regulatory reform, and shifting insurance mechanisms, patients' access to timely and evidence-based care remains unclear. This panel presents four empirical studies that examine system-level changes across public and private insurance sectors, including Medicare, Medicare Advantage, the ACA Marketplace, and high-deductible health plans. Together, the studies explore how market dynamics and insurance design influence access to care across a range of populations, from those with chronic illness to the general population navigating coverage options in increasingly complex insurance markets. 

The first paper, Trends in Market Concentration in the ACA Individual Health Insurance Markets (Anderson et al.), explores how insurer participation and competition have changed across U.S. counties from 2015 to 2023. While the number of insurers per market has grown, analysis of the Herfindahl–Hirschman Index reveals persistent and meaningful variation in competition levels. These insights offer a more nuanced view of how managed competition has evolved under the Affordable Care Act and its implications for premium levels and consumer choice.  

The second paper, Dialysis Facility Acquisition and Access to Transplant (Cai et al.), examines how consolidation in the dialysis industry affects kidney transplant access for patients with end-stage renal disease (ESRD). Using a stacked difference-in-differences approach with national data from over 8,000 facilities, the study finds that acquisitions by large dialysis chains are associated with prolonged wait times to transplant—particularly for younger and Black patients—raising concerns about equity in light of federal kidney care priorities. 

In the third paper, The Effect of Acquiring Health Insurance on Health Outcomes (Marquardt et al.), the authors leverage a regression discontinuity design around Medicare eligibility at age 65 to estimate the causal effects of health insurance coverage on physical, cognitive, and mental health outcomes using American Community Survey data from 2008–2023. The study finds that gaining insurance leads to significant improvements in health status, with particularly large benefits prior to the ACA and among historically underserved groups, highlighting the protective role of Medicare as Baby Boomers age. 

Finally, Do Common Insurance Mechanisms Support Receipt of Evidence-Based Care? (Gidwani) investigates whether high-deductible health plans (HDHPs) enable access to recommended care for chronically ill adults. Using MarketScan claims data and quasi-experimental methods—including instrumental variables with difference-in-differences models —the study finds that HDHPs significantly reduce the receipt of evidence-based care across multiple conditions, raising questions about the adequacy of current insurance designs for high-need populations. 

Together, these studies offer timely, policy-relevant evidence on how evolving insurance markets influence access to care. By examining both public and private coverage models, the panel contributes to ongoing discussions about equity, affordability, and the role of insurance design in shaping health outcomes.

Policy Area

• Health Policy

Chair

• Rebecca Myerson, Emory University

Discussants

• Petra Willis Rasmussen, RAND Corporation

• Matthew Lavallee, Johns Hopkins University

Organizer

• Sih-Ting Cai, Indiana University

Individual Presentations

• Trends in Market Concentration in the ACA Individual Health Insurance Markets - Presenting Author: David M Anderson, University of South Carolina; Non-Presenting Co-Author: Daniel Ludwinski, Emory University; Non-Presenting Co-Author: Sayeh S Nikpay, Vanderbilt University; Non-Presenting Co-Author: Ezra Golberstein, University of Minnesota

• Dialysis Facility Acquisitions and Their Impact on Operating Structure and Kidney Transplant Access - Presenting Author: Sih-Ting Cai, Indiana University; Non-Presenting Co-Author: Seth Freedman, Indiana University

• The Effect of Acquiring Health Insurance on Health Outcomes: Evidence from Turning 65 in the U.S - Presenting Author: Kristn F Butcher, Federal Reserve Bank of Chicago; Non-Presenting Co-Author: Kelli Marquardt, Federal Reserve Bank of Chicago

• Do Common Insurance Mechanisms Support Receipt of Evidence-Based Care? A National Analysis of Chronically-Ill Persons - Presenting Author: Risha Gidwani, University of Colorado Denver