Übersterblichkeit im Kontext der COVID-19-Pandemie in Deutschland

International comparisons of the disease burden of the coronavirus disease 2019 (COVID-19) pandemic often used excess mortality as an important criterion for assessing the effectiveness of interventional measures. For Germany there were strong discrepancies between the excess mortality estimates from various studies. As the estimates were based on different models and data sources, a detailed analysis of the methodology used is necessary. This study used different methods to estimate excess mortality in Germany from January 2020 to October 2023. The aim was to identify temporal and spatial patterns of excess mortality and to determine the effects of different methodological approaches. In the reference period 2011–2019, a regression model for the mortality rates of the Federal States was fitted, which provided the basis to calculate expected monthly deaths in the index period 2020–2023. The model took into account the population structure, temperature, influenza activity and socioeconomic deprivation. The excess mortality as the difference between observed and expected deaths was compared with the deaths attributed to COVID-19 in the index period. As a simple alternative model the excess mortality in the index period was estimated only on the basis of sex-specific and age-specific median mortality rates per calendar month in the reference period. Excess mortality and deaths attributed to COVID-19 showed clear temporal and spatial patterns. From Autumn 2021 onwards the number of deaths attributed to COVID-19 was lower than the excess mortality. Saxony, Saxony-Anhalt and Thuringia had the highest excess mortality. The simplified excess mortality estimates sometimes led to widely differing results. Temporal and spatial patterns indicate that discrepancies between excess mortality and deaths attributed to COVID-19 are due to underreporting of COVID-19 mortality. If strong influences on mortality are not taken into account, this leads to distorted estimates of excess mortality.