Studies on COVID-19 lethality: Causes and dynamics at German University Hospitals

Background: In the initial phase of the COVID-19 pandemic, a lower incidence and death rate was observed in Germany compared to its neighbouring countries, but some studies showed comparatively high death rates in ventilated COVID-19 patients. Methods: In this retrospective analysis, hospital stays of COVID-19 patients at 14 German university hospitals were analysed. For this purpose, local data integration centres of the German Medical Informatics Initiative (MII) combined their data to present death rates in different subgroups depending on gender, age, length of stay in the intensive care unit, ventilation and in combination with different comorbidities. Results: The total lethality rate in 1,318 COVID-19 patients was 18.8 %. In ventilated cases, the lethality rate was 38.8%. Common comorbidities were renal insufficiency (35.2 %), aplastic and other anaemia (26.0 %) diabetes mellitus (21.1 %). The average length of stay was 18 days, or 28 days in case of ventilated patients. Lethality decreased from 20.7 % to 12.7 % over the observation period. Conclusion: The observed decline in lethality rates may be explained with the continuous optimisation of COVID-19 treatment, increasing experience and improved therapy recommendations. The progress made so far by the MII allows cross-consortium analyses to be carried out just in time to better address the challenges of the COVID-19 pandemic.