Regional Disparities in Home-Based Medical Care Utilization in Japan: Ecological Study of Nationwide Claim Data.

Abstract

Japan faces demographic challenges with rapid population aging and decline, especially in rural areas with low population density, high proportions of older adults, and limited medical accessibility. Home-based medical care has emerged as a potential solution to expand healthcare capacity and reduce health disparities in these areas. To quantify regional variations in home-based medical care utilization and to examine their association with Rurality Index for Japan (RIJ), a composite measure incorporating population density, geographical distance, and climatic factors. Ecological study using open data from the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) for 2019-2020. In total, 335 secondary medical areas (SMAs) and 47 prefectures across Japan. Standardized Claim Ratio (SCR) for four indicators of home-based medical care: regular home visits, emergency house calls, death certificates, and end-of-life care; and their correlation with RIJ. Significant regional disparities were observed with maximum/minimum ratios of 82.0, 210.3, 33.2, and 29.5 for regular home visits, emergency house calls, death certificates, and end-of-life care, respectively. Spearman's rank correlation coefficients between SCR and RIJ were -0.619 for regular home visits, -0.518 for emergency house calls, 0.225 for death certificates, and -0.541 for end-of-life care (all P < 0.001). Several dozen-fold regional disparities exist in home-based medical care utilization across Japan, with higher rurality associated with lower utilization of most services. These findings suggest geographical barriers significantly influence access to home-based medical care. Our findings highlight the utility of RIJ as an effective measure to identify and address these healthcare disparities, informing targeted policy interventions to improve equitable access to home-based medical care in rural Japan.