High-Heat Days and Presentations to Emergency Departments in Regional Victoria, Australia.

Heat kills more Australians than any other natural disaster. Previous Australian research has identified increases in Emergency Department presentations in capital cities; however, little research has examined the effects of heat in rural/regional locations. This retrospective cohort study aimed to determine if Emergency Department (ED) presentations across the south-west region of Victoria, Australia, increased on high-heat days (1 February 2017 to 31 January 2020) using the Rural Acute Hospital Data Register (RAHDaR). The study also explored differences in presentations between farming towns and non-farming towns. High-heat days were defined as days over the 95th temperature percentile. International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Australian Modification (ICD-10-AM) codes associated with heat-related illness were identified from previous studies. As the region has a large agricultural sector, a framework was developed to identify towns estimated to have 70% or more of the population involved in farming. Overall, there were 61,631 presentations from individuals residing in the nine Local Government Areas. Of these presentations, 3064 (5.0%) were on days of high-heat, and 58,567 (95.0%) were of days of non-high-heat. Unlike previous metropolitan studies, ED presentations in rural south-west Victoria decrease on high-heat days. This decrease was more prominent in the farming cohort; a potential explanation for this may be behavioural adaption.