Probabilistic Model to Analyze Patient Accessibility to Medical Facilities Using Geographic Information Systems

In this study, we developed a probabilistic model to analyze patient accessibility to hospitals by using a geographic information system (GIS). In the consideration of patient accessibility, we do not have correct patient addresses because of the laws related to protection of a patient's personal information. Thus, we use a representational place in the city or the ZIP code of the area. However, this may lead to a decline in the accuracy of the analysis. In this study, we used a 500-m mesh map and obtained the population gender and age group data from the national census data, in order to estimate the patient accessibility to medical facilities in small areas. We calculated the probability that a patient lives in each mesh on the basis of the population gender and five-year age group data. We selected the appropriate mesh on the basis of this probability and investigated the time distance from the estimated mesh to each hospital by using a GIS. As a result, we calculated the time distance and its distribution by using the proposed method from limited available information. Further, we found that in the target cities, the average time distance to hospital calculated using the proposed method was longer than that calculated by using a previous method; the percentage of patients who took more time than the city average to reach a hospital by using the proposed method. This method is very useful when planning the geographical resource allocation of medical services