Injury mortality and accessibility to emergency care in Japan: an observational epidemiological study

BACKGROUND Unintentional injury is a major cause of death across the globe. The accessibility to emergency medical services may affect the rate of preventable trauma deaths. The purpose of this study was to analyze the accessibility to emergency medical hospitals in municipalities in Japan and to clarify whether accessibility was associated with the mortality rate attributed to unintentional injuries. METHODS An observational epidemiological study was conducted in all 1,742 municipalities in Japan. Measurements assessed were population size, accessibility to emergency hospitals, and mortality rates attributed to unintentional injuries. Accessibility of each municipality to their nearest emergency hospital was calculated with a computer simulation using a geographic information system. After calculating demographic statistics and the Gini coefficient of accessibility, multivariate analyses were used to examine the correlation between accessibility time and mortality. Municipalities were divided into six groups according to accessibility time, and we then performed a correlation analysis between accessibility time and mortality using analysis of covariance. RESULTS The median time of accessibility to emergency hospitals was 34.5 minutes. The Gini coefficient of accessibility time was 0.410. A total of 385 municipalities (23.4%) had an accessibility time of over 60 minutes. Accessibility was significantly related to mortality (beta coefficient =0.006; P<0.001). The mortality rate in municipalities with an accessibility time of <15 minutes was lower than that in all other groups. The mortality rate in municipalities with an accessibility time of 15-30 minutes was lower than that in municipalities with an accessibility time of >30 minutes, and the mortality rate in municipalities with an accessibility time of 30-45 minutes was lower than that in municipalities with an accessibility time of 60-90 minutes (P<0.001). CONCLUSION The geographical disparities for emergency care accessibility were related to the rate of death by unintentional injury. Improving accessibility to emergency hospitals could help decrease the mortality rate of preventable trauma. Meanwhile, our findings suggest the need for substantially shorter accessibility times to emergency care facilities in many municipalities in Japan.