Spatiotemporal variations in ambulance demand: towards equitable emergency services in Sweden

Abstract

This study investigates the spatiotemporal variations in ambulance demand in southern Sweden, and how land use factors and sociodemographic factors are associated with variations in demand. A standardized ambulance demand ratio (SADR) indicating whether the risk of requiring an ambulance exceeded the expected was calculated using ambulance dispatch data in southern Sweden in 2018. Spatial analysis using a geographic information system (GIS) and spatial statistical methods underlie the methodology. Findings show that although rural areas are associated with a higher risk of requiring an ambulance (especially in daytime), this risk may be obscured by the more numerous dispatches occurring in urban areas. The increased risk in areas with bars and nightclubs, schools, industrial areas or road crossings reflects temporal variations in people’s routine activities. By dictating how and when population’s reshuffle, land use factors can help explain variations in risk for requiring an ambulance. Confirming previous research, areas with a higher share of older adults are associated with a higher ambulance demand while areas with a high median income are associated with lower demand. Population size may be an inadequate indicator of ambulance demand. Planning should account for daily changes in population sizes and compositions as this impacts ambulance demand.