Effects of extreme temperature on morbidity, mortality, and case severity in German emergency care

Climate change affects the frequency and intensity of extreme heat and cold events, which can have severe health repercussions. Therefore, we investigated the effects of extreme ambient temperature on emergency care-associated morbidity, mortality, and case severity in Germany. We analyzed all somatic emergency admissions (EA) to German hospitals from 2010 to 2019. Using weather station data from the German Meteorological Service, we estimated immediate and 28-day lagged effects of extreme heat (99th percentile of mean temperature) and extreme cold (1st percentile of mean temperature) in a two-stage time-series analysis using a distributed lag non-linear model. 78,486,368 EAs were included in the study. The cumulated immediate and lagged effect of temperature indicated that extreme cold decreased the EA risk but increased the fatal EA risk and case mortality. In turn, extreme heat increased the EA risk, the fatal EA risk, and the case mortality. The 1% (5%) coldest days prevented 3,400 (11,950) EAs but led to 450 (2150) additional in-hospital deaths following an EA. The 1% (5%) hottest days resulted in 4,900 (20,550) additional EAs and 300 (1,050) additional deaths. Generally, the effect of extreme cold unfolded over four weeks, while the effects of heat manifested more promptly and subsided virtually within the first week. Our findings highlight that extreme heat is associated with an increase in emergency care-associated morbidity, while both extreme heat and cold are associated with a higher emergency care-associated mortality and case severity in Germany, urging greater efforts to curb the health effects of extreme temperatures.