Survey-Reported Coverage in 2019-2022 and Implications for Unwinding Medicaid Continuous Eligibility.

Importance: Policy changes and the COVID-19 pandemic affected health coverage rates, and the "unwinding" of Medicaid's continuous coverage provision in 2023 and 2024 may cause widespread coverage loss. Recent coverage patterns in national survey and administrative data can inform these issues.

Objective: To assess national and state changes in survey-based Medicaid, private insurance, and uninsured rates between 2019 and 2022, as well as how these changes compare with administrative Medicaid enrollment totals.

Design, Setting, And Participants: This cross-sectional study analyzes nationally representative survey data for all US residents in the American Community Survey (ACS) from 2019 to 2022 compared with administrative data on Medicaid and the Children's Health Insurance Program from the Centers for Medicare & Medicaid Services (CMS). Data analysis was conducted between June 2023 and January 2024.

Exposures: The COVID-19 pandemic, the Medicaid continuous coverage provision, and policy efforts to increase Marketplace coverage.

Main Outcomes And Measures: Medicaid coverage (self-reported [ACS] and administratively recorded [CMS]), survey-reported uninsured, Medicare, and private insurance status.

Results: A nationally representative sample consisted of 12 506 584 US residents of all ages (survey-weighted 59.7% aged 19-64 years and 50.6% female). CMS statistics showed an increase in Medicaid coverage of 5.2 percentage points as a share of the population from 2019 to 2022. However, changes in the uninsured rate and survey-reported Medicaid were smaller: -1.2 (95% CI, -1.3 to -1.2) percentage points and 1.3 (95% CI, 1.2-1.4) percentage points, respectively. There was a 3.9 percentage point increase in the ACS's "undercount" of Medicaid enrollment, compared with CMS data, from 2019 to 2022. This undercount was larger among children than adults but smaller in states that recently expanded Medicaid. Rates of additional forms of coverage (such as private insurance) among those in Medicaid also grew during this time.

Conclusion And Relevance: In this cross-sectional study, the uninsured rate declined considerably from 2019 to 2022 but was just one-fourth as large as the growth in administrative Medicaid enrollment under the pandemic continuous coverage provision. Survey-based Medicaid growth was far smaller than administrative growth. This suggests that many people who remained enrolled in Medicaid during the pandemic did not realize that their coverage had continued. These findings have implications for projecting uninsured changes during unwinding, as well as the effect of continuous coverage policies on continuity of care.