The impact of Medicaid on medical utilization in a vulnerable population: Evidence from COFA migrants

Area of Science:

• Public Health
• Health Services Research
• Health Policy

Background:

• In March 2015, Hawaii altered Medicaid eligibility for most migrants from Compact of Free Association (COFA) nations.
• COFA migrants were directed to obtain private insurance via Affordable Care Act (ACA) marketplaces.

Purpose of the Study:

• To assess the impact of reduced Medicaid coverage on healthcare utilization among COFA migrants in Hawaii.
• To determine if increased private insurance uptake offset decreased Medicaid utilization.
• To investigate the role of uninsurance versus cost-sharing in utilization changes.

Main Methods:

• Analysis of statewide hospital discharge data before and after the policy change.
• Comparison of healthcare utilization trends (hospitalizations, ER visits) funded by Medicaid, private insurance, and uninsurance.
• Exploitation of policy variation to distinguish between uninsurance and cost-sharing effects.

Main Results:

• Medicaid-funded hospitalizations decreased by 31% and ER visits by 19% among COFA migrants.
• Private insurance utilization increased but did not compensate for the decline in Medicaid-funded care.
• A significant rise in uninsured emergency room visits was observed post-policy change.
• Evidence suggests increased uninsurance, not higher cost-sharing, drove the utilization declines.

Conclusions:

• The policy change led to reduced healthcare access for COFA migrants in Hawaii.
• The shift to private insurance was insufficient to maintain previous utilization levels.
• Increased uninsurance is a key consequence of restricting Medicaid eligibility for this population.