Association Between Remoteness to a Health Care Facility and Incidence of Ambulance Calls in Rural Areas of Japan

Objectives: Whether traffic remoteness from health care service in rural areas influences usage of ambulance service has not been well investigated. This study aimed to evaluate the relation between remoteness to health care facilities and incidence of ambulance calls in rural areas of Japan. Methods: We analyzed 155 rural communities of Hiroshima. Data were obtained on all ambulance dispatches from 2010 to 2012. Driving time was calculated from each community to the closest primary/secondary and tertiary health care facility (equivalent to tertiary emergency care centers). We estimated the incidence rate and the incidence rate ratio (IRR) of ambulance calls for each 10-minute increase in the driving time, using generalized log-linear regression models, and evaluated the effect among each specific subgroup of emergency level and season. Results: During the study period, the median incidence rate was 436 per 10 000 people in targeted communities. When driving time to the closest primary/secondary facility increased by an increment of 10 minutes, there was a significant increase in the IRR of ambulance calls, especially during colder seasons (IRR: 1.29 [95% confidence interval: 1.11-1.49]), and this relation was also obtained for most emergency levels. In comparison, there was no such increase in IRRs observed for driving time to a tertiary facility. Conclusion: This study indicated a positive association between remoteness to primary/secondary medical facilities and the frequency of ambulance calls. The remoteness to a primary/secondary health care may induce an increase in ambulance calls, particularly during cold seasons.