Accessibility to medical institutions in Aichi Prefecture: A geographic information systems-based analysis

We investigated the geographic accessibility of medical institutions in Aichi Prefecture, Japan, using Geographic Information Systems (GIS). Three facility types-pharmacies, hospitals, and clinics-were analyzed across 11 secondary healthcare regions. Accessibility was evaluated based on spatial proximity by calculating population and elderly population coverage rates, defined as the proportion of residents located within the vicinity of medical institutions. Catchment areas were defined by travel mode: 400-m buffers represented a 5-min walk, and 2-km buffers approximated a 5-min drive. We tested how results changed when buffer distance varied from 300 m to 3 km. To assess proximity to transit stops and stations, 400-m buffers were generated around bus stops and train stations. Population data at the small-area level (chō-chō-aza units) from the 2020 Census of Japan were overlaid with buffer zones, and areal weighting was applied to estimate populations within buffers. Accessibility indicators were compared across regions and age groups. In the Nagoya-Owari Central region, nearly all residents were covered within 2 km of facilities (pharmacies 100%, hospitals 97%, clinics 100%), whereas the Higashimikawa Northern region had the lowest coverage (pharmacies 59%, hospitals 36%, clinics 72%). Elderly population coverage was lower than total population coverage in rural areas. In urban regions, coverage rates within 400 m of bus stops and train stations reached 96%, whereas in rural regions, they declined to below 50%. Overall, urban areas benefit from concentrated healthcare resources and extensive transit networks, whereas rural and mountainous regions remain underserved. Private-vehicle use may expand potential geographic reach for some residents; however, this does not demonstrate effective access to healthcare, particularly among older adults with mobility limitations. High proximity-based coverage does not imply timely or adequate service utilization. Geographic and demographic perspectives must be integrated into healthcare policy to support community care and sustainable resource allocation under population aging.