[Study of factors that influence the use of ambulances in Japanese prefectures]

The objective of this study was to clarify the factors that influence the rate of patient-carriage by ambulances in Japanese Prefectures.

The study was conducted using data on cases of patients with mild conditions carried by ambulances in Japanese prefectures in 1993, concentrating the factors that influence the rate of usage. The cases were analyzed focusing on three major types of medical emergencies (accounting for 93.4% of the total): sudden illnesses, traffic accidents and general injuries. SPSS for Windows was used for statistical analysis.

Data analysis by age group and type of medical emergency showed a positive correlation (r > 0.7) for the rate of cases with mild conditions carried by ambulances in all age groups (early childhood, adolescence, adult and senior) and the three major types of medical emergencies. Particularly, a strong correlation (r > 0.9) was observed with regard to patients suffering from sudden illnesses and general injuries. Multiple regression analysis showed that the rate for patients with mild cases carried by ambulances was higher in prefectures where; (1) there were more cases of administrative litigation related to individuals' rights, and (2) there were many nuclear families that tended to lack the capacity for family care. In addition, it also became evident that the rate for patients with mild injuries from traffic accidents was higher in prefectures where; (1) the rate for male-driver license holders for small- and medium-size cars was higher, and (2) the ratio of numbers of vehicles to total roadway area was higher.

The findings suggest that factors unrelated to medical emergencies have a major influence on use of ambulance. Reevaluation of policy in order to promote appropriate utilization is necessary.