Mapping heat-related morbidity burden attributable to human-induced climate change across 460 communities of Victoria, Australia

Abstract Background With the continued rise in global temperature, the health risks associated with heat have become increasingly prominent. This study aims to assess and map the risk and cost of hospital admissions and emergency department (ED) visits attributable to heat exposure across local communities in Victoria, Australia, and quantify the impact of human-induced climate change. Methods We collected daily hospital admissions and ED visits during the hot seasons from 2014 to 2019 in Victoria, Australia. Using a standard time-series Poisson model and a random-effects meta-analysis, we estimated the heat-attributable burden of hospital admissions as well as ED visits at both the community and statewide levels, and further quantified the excess heat-related burden attributable to human-induced climate change. Results This study included 6,301,710 all-cause hospital admissions and 3,812,690 all-cause ED visits across 460 communities. From 2014 to 2019, heat exposure was responsible for 4574 (95% confidence interval [CI]: 4486, 4628) hospital admissions and 10,920 (95%CI: 10,789, 11,016) ED visits per year in Victoria, resulting in healthcare costs of AU$ 23.30 (95%CI: 22.86, 23.58) million and AU$ 7.03 (95%CI: 6.94, 7.09) million, respectively. Notably, the heat-related burden was particularly pronounced in women, rural areas, and northern communities. Human-induced climate change increased heat-related hospitalizations by 27.25% and ED visits by 16.46%. Urban areas were more sensitive to human-induced climate change than rural areas, with human-induced climate change contributing to 31.28% of heat-related hospitalizations and 21.14% of heat-related ED visits. Conclusion Heat exposure was associated with increased risks of hospital admissions and ED visits in Victoria, particularly in women, rural areas, and northern communities, contributing to approximately AU$30 million in healthcare costs annually. Human-induced climate change had further intensified these heat-related burdens, with urban areas exhibiting greater sensitivity to human-induced climate change than rural areas.