Geospatial and insurance barriers to allergist access across the Midwest.

Area of Science:

• Allergy and Immunology
• Health Services Research
• Rural Health

Background:

• Geographic and insurance barriers limit allergist access in the U.S.
• Previous studies reported a 55.5% national Medicaid acceptance rate among allergists.
• Midwest region's allergist access, particularly Medicaid acceptance, remained uncharacterized.

Purpose of the Study:

• To assess Medicaid acceptance rates among allergist-immunologist practices in the 12 U.S. Midwest states.
• To measure appointment wait times for allergy services.
• To evaluate county-level spatial accessibility to allergists.

Main Methods:

• A telephone survey of 1,301 allergist-immunologist practices was conducted between July and November 2025.
• County-level accessibility was calculated using the 2SFCA (two-step floating catchment area) method.
• Data collection focused on Medicaid acceptance, wait times, and geographic distribution.

Main Results:

• 74.1% of surveyed allergists accepted Medicaid, an increase from previous national estimates.
• Only 6.6% of practices offered appointments within two weeks.
• The average distance to the nearest allergist was 83.6 miles, with lower accessibility in primary care shortage areas.

Conclusions:

• Overlapping barriers of insurance, geography, and provider shortages disproportionately affect rural and publicly insured patients.
• Gaps in specialty care exacerbate existing primary care deficits.
• Urgent need for workforce expansion, improved Medicaid reimbursement, and innovative care delivery models to enhance allergy access.