Association between number of hospitalizations of older adults and heatwaves in Slovenia 1999-2018

Abstract Background Heatwaves frequency, intensity, and duration increase with global climate change. The association between heat and mortality in older adults is well documented, but less is known about associations with hospitalizations. Knowing which diseases contribute to a higher number of hospitalizations during heatwaves is important for planning appropriate public health preventive measures. Methods We assessed short-term association between the number of hospitalizations for older adults (75+ years) and heatwaves in the years 1999 to 2018 in Slovenia. We estimated the relative risks (RR) with 95 % confidence interval for the number of hospitalizations for the observed diagnosis (all causes, circulatory, respiratory, endocrine and genitourinary diseases) and gender associated with heatwaves in Slovenia for each year, comparing the number of hospitalizations during heatwaves with reference days. Results We could not find an association between heatwaves and hospitalizations for all cause hospitalizations in all observed years. In some years the association was even negative. In cause specific analyses heatwaves were associated with increased hospitalizations for endocrine diseases in 2012 (32%; 95% CI: 1%, 73%), 2013 (23%; 95% CI: 5%, 33%), 2014 (48%; 95% CI: 4%, 110%) and 2015 (42%; 95% CI: 7%, 89%), but not for cardiovascular, respiratory and genitourinary diseases. Conclusions Older adults are most susceptible to the effects of extreme heat due to physiological changes that occur with aging, chronic diseases, certain medications, a sedentary lifestyle and social isolation. The results of our study will help in planning appropriate preventive public health measures to better protect older adults during the next heatwaves in Slovenia. Key messages • Heatwaves will become longer, more frequent and more intense in the near future. • Endocrine diseases are the most important cause for hospitalization during heatwaves. Public health measures shoud adress these most vulnerable groups.