The link between temperature and hospitalizations in Germany: a focus on regional characteristics

Abstract Background Exposure to extreme temperature is associated with increased unplanned hospitalizations, but it remains unclear whether and why vulnerability varies across regions. This study investigates how regional characteristics modify the relationship between temperature and emergency hospitalizations in Germany. Methods We analyzed weekly emergency hospital admissions by German municipalities from 2005 to 2021 using the Diagnosis-Related Groups Statistic, linked with high-resolution temperature data from the E-OBS database. We calculated the number of days per week falling into one of eleven temperature bins, with 9-16 °C defined as the reference (comfort zone). A municipality-level fixed effects Poisson model was fitted and adjusted for temperature, week, year, gender, and age group. To determine effect modification, we fit stratified models by socioeconomic deprivation, urbanicity, life expectancy, and age structure of the region. Results We observe 112,480,765 emergency hospitalizations over the study period. One additional day above the comfort zone temperature was associated with an increased hospitalization rate in the same week, and minor changes in the following week. In contrast, one additional day below the comfort zone was associated with a decreased hospitalization rate in the same week but an increase in the following week. Preliminary results suggest effect modification by regional characteristics, particularly by socioeconomic deprivation. Conclusions The unplanned character of increased hospitalizations following extreme temperatures presents challenges for adequate care provision. We highlight that some regions, especially those with higher socioeconomic deprivation, may be more vulnerable to the growing health consequences of climate change in Germany. Key messages • Regional characteristics modify the association between extreme temperatures and emergency hospitalizations in Germany. • In the face of climate change, focusing on these regional characteristics allows for understanding which regions need to be prioritized for adequate care provisioning.