2023 HSR&D/QUERI National Conference

4114 — Medicaid Expansion was Associated With Longer Wait Times for Specialty Care

Lead/Presenter: Kevin Griffith,  Partnered Evidence-Based Policy Resource Center (PEPReC)
All Authors: Asfaw DA (Partnered Evidence-Based Policy Resource Center, Boston University), Aswani, MS (University of Alabama at Birmingham) Besaw, RJ (Vanderbilt University Medical Center) Griffith, KN (Partnered Evidence-Based Policy Resource Center, Vanderbilt University Medical Center)

Since passage of The Affordable Care Act (ACA) more than a decade ago, 39 states expanded Medicaid to low-income adults. Medicaid expansion has been associated with increased access to care and health services utilization, and simulated patient (“secret shopper”) studies documented modest changes in appointment wait times in expansion states. However, these findings have yet to be validated in large administrative datasets. Thus, we assessed trends in appointment wait times for specialty care following state Medicaid expansions.

We obtained administrative data from the Veterans Health Administration (VHA) on all appointments for specialty care during 2011-2021. The VHA provides care to 9 million Veterans, but also contracts with community-based medical professionals to care for hundreds of thousands of Veterans each year. We limited our sample to new clinical relationships and excluded states that expanded Medicaid income eligibility prior to the ACA. Our unit of analysis was the individual appointment (N = 154,416,019). We first “stacked” our data to adjust for differential expansion timing and potential effect heterogeneity. We created event-specific datasets for each expansion state including “clean” control states that never expanded Medicaid, which were then stacked in relative time. Next, we used interrupted time series models to estimate changes in wait times 2011-2021, stratified by expansion year and site of care (VHA/community). Lastly, we estimated difference-in-difference (DID) models to assess changes in waits for each year post-expansion. All models were adjusted for Veterans’ age, income, sex, specialty, month, and state, with standard errors clustered by state.

In the year prior to expanding, expansion states experienced mean wait times of 31.2 and 46.3 days for VHA and community care, respectively. Non-expansion states experienced mean wait times of 30.1 and 49.2 days for VHA and community care, respectively. VA wait times decreased by 5.2 days (95% CI -5.7, -4.7) in expansion states and by 0.1 days in non-expansion states (95% CI 0.1, 0.2). In expansion states, community waits peaked two years post-expansion (+11.1 days, 95% CI 10.5, 11.7) while non-expansion saw a 0.8-day decline (95% CI -0.9, -0.6). In DID models, expansion was associated with increased community waits during the first (+2.4 days, 95% CI 1.9, 2.9) and second year post-expansion (+9.0 days, 95% CI: 8.4, 9.5) before returning to pre-expansion levels. In contrast, expansion was not associated with significant changes in VHA wait times until waits decreased in year three (-5.1 days, 95% CI -5.6, -4.5). Additionally, we observed significant treatment effect heterogeneity between early vs. late expansion states.

Our results suggest that improved care access without concomitant changes in provider supply may lead to increased wait times, at least in the short term. Increased access to private-sector care following Medicaid expansions were associated with lower wait times, which may be attributable to reductions in Veterans’ reliance on the VHA for services.

States should consider strategies, such as expanded telehealth and mobile health care teams, to ensure an adequate supply of providers to meet Medicaid enrollee’s health needs.