Introduction 

Heatwaves induce excess mortality and increase the impact of certain comorbidities. However, there is a lack of perspective on the influence on emergency room visits outside of a few very specific heat-related pathologies. The objective of the study is to investigate the impact of heat on emergency room visits for three morbid syndromes not currently routinely monitored in France: acute renal failure, cardiac decompensation, and myocardial ischemia.

Methods 

The study period covers the summers (June 1 ^to  September 15) of 2015 to 2022 for the 12 departments of the Auvergne-Rhône-Alpes region. Health data were extracted from the SurSaUD ^® syndromic surveillance system (Health Surveillance of Emergencies and Deaths). A multivariate analysis of the average number of daily visits according to the periods of actual exceedance of the heatwave threshold and the vigilance periods was carried out by negative binomial regression.

Results 

A total of 14,060 emergency department visits for acute renal failure, 29,841 for cardiac decompensation and 17,749 for myocardial ischemia occurred between 2015 and 2022 during the study periods in Auvergne-Rhône-Alpes. The risk of emergency department visits for acute renal failure increases by +47% (95% confidence interval, 95% CI: [39-56]) when temperatures exceed meteorological alert thresholds, independently of sex, age, department, day and month, or in the event of a maximum temperature >24°C, with an increasing risk in the event of very high temperatures. These effects are not highlighted for emergency department visits for cardiac decompensation and myocardial ischemia.

Conclusion 

The risk of emergency room visits for acute renal failure increases during heat waves and should encourage the implementation of specific measures to prevent this pathology during the summer.