Patient concentration to large-sized hospitals has been a problem in Korea in recent years. The same problem lies in prehospital Emergency Medical Services (EMS) in highly urbanized city of Seoul; it is known that patients prefer emergency departments of large-sized hospitals, expecting a better care and a faster admission. This concentration phenomenon is possible because of large number of available options that patients can choose from.The objective of this study is to examine the hospital choice of emergency patients by comparing the cost of choosing the actual and alternative options. We define and measure the proximity index of emergency hospitals that are accessible by patients transported by ambulance within a specific travel time threshold.
We utilize the actual incident locations and road networks to calculate the routing of ambulances and corresponding travel times using Geographic Information Systems (GIS). The proximity index is calculated and compared within hospitals, age groups, conscious states, and disease subgroups. The results show that one of the biggest hospitals in the city is preferred by people although the cost of choosing is approximately a double of the overall average and that non-urgent patients tend not to choose the best option. This study suggests that efficient decision making in prehospital EMS may contribute in relieving the patient concentration in emergency departments.