Trends in the Impact of Medicaid Expansion on the Use of Clinical Preventive Services

Introduction: This study aims to evaluate the trends in the impact of Medicaid expansion on the use of selected recommended clinical preventive services and examine the differences in use by income level over time.

Methods: The data were obtained from the 2011-2019 Behavioral Risk Factor Surveillance System and were analyzed in 2021. This study conducted a difference-in-differences analysis of the association between Medicaid expansion and the use of 5 clinical preventive services, including colon/breast/cervical cancer screenings, HIV testing, and influenza vaccination. Annual percentage change was applied to assess the trends in the impact of Medicaid expansion on the use of clinical preventive services.

Results: The use of all the 5 clinical preventive services varied over time. In almost every year, the use of 4 clinical preventive services (all but HIV testing) among Medicaid expansion states was higher than that among the nonexpansion states. People with lower income used 4 clinical preventive services (all but HIV testing) less frequently than those with higher income, regardless of their residence in expansion or nonexpansion groups. Among the lower-income group, the use of 5 clinical preventive services increased after Medicaid expansion almost every year, with the use of colon cancer screening and HIV testing reaching statistical significance and the impact of Medicaid expansion in the use of each clinical preventive service kept stable from 2014 to 2019.

Conclusions: These findings provide evidence that Medicaid expansion may be associated with sustainably increased use of the selected recommended clinical preventive services among the lower-income population and that Medicaid expansion to reduce financial barriers may be an effective strategy to improve population health.