The odds and costs of ambulance attendances associated with heatwave severity in older adults of queensland, Australia.

Ambulance attendances have been increasingly reported to be a sensitive indicator of increased health service utilisations during heatwaves. This study estimated the odds and costs of ambulance attendances associated with heatwave severity (low-intensity, severe, and extreme) in older adults (≥ 65 years) from 1st January 2010 to 31st December 2018 in the State of Queensland, Australia. The findings showed that low-intensity, severe, and extreme heatwaves were associated with 1.4% (95% confidence interval: 0.3%, 2.5%), 4.1% (2.1%, 6.1%), and 9.7% (7.3%, 12.0%) increased odds of ambulance attendances for older adults, respectively. The increased odds of ambulance attendances elevated with age during extreme heatwaves (peaking at 11.7% for ≥ 85 years). Heatwaves were associated with additional ambulance attendance costs of $237,141 per year for older adults in Queensland, with 62.2% and 31.7% of these costs from low-intensity and severe heatwaves, respectively. These findings call for research to address critical knowledge gaps around appropriate early warning system notifications for low-intensity and severe heatwaves, given their evidenced impacts on individuals and emergency health systems.