Risk, Attributable Fraction and Attributable Number of Cause-Specific Heat-Related Emergency Hospital Admissions in Switzerland

Objectives We assessed the relationship between heat and emergency hospital admissions (EHAs) in Switzerland using clinically relevant metrics.Methods Applying distributed lag non-linear models, we investigated temperature-admission associations between May and September 1998-2019 for various disease groups, by age class and gender. We estimated the relative risk (RR) for moderate (29 degrees C) and extreme (34 degrees C) daily maximum temperatures relative to disease-specific optimum temperature, and calculated attributable fractions (AFs) for hot days and the following week. We also calculated the total number of heat-related EHAs.Results We attributed 31,387 (95% confidence interval: 21,567-40,408) EHAs to above-optimal temperatures, 1.1% (0.7%-1.4%) of the total. Extreme temperatures increased the EHA risk for mental, infectious and neurological diseases. We observed particularly high AFs due to extreme heat for dehydration (85.9%, 95% CI: 82.4%-88.8%) and acute kidney injury (AKI, 56.1%, 95% CI: 45.3%-64.7%). While EHA risk generally increased with age, we also found high RRs for infectious diseases in children (0-15 years) and AKI in young adults (15-64 years).Conclusion Hot weather increases the EHA risk in Switzerland. Therefore a comprehensive clinical and public health response is needed.