High variability of COVID-19 case fatality rate in Germany

DOI: https://doi.org/10.21203/rs.3.rs-536841/v1


During the first wave of the COVID-19 pandemic high case fatality rates (CFR) were noticed. Due to the dire consequences WHO guidelines recommended immediate intubation for patients with dyspnoea which has since been questioned after reviewing the initial clinical outcome.

Methods: PCR confirmed infection rates along with mortality data was obtained for all German districts from 27 Jan 2020 until 15 Feb 2021 using official data sources. A moving average CFRt was constructed by dividing disease related deaths two weeks after a given index days by the number of infections two weeks prior to that date. In addition to an international comparison, mortality data between the second and third largest German cities were also compared.

Results: Mean CFR is estimated to be 2.92 based on 71.965 fatalities and 2.465.407 cases. There was a large regional scattering of CFRs across the regional districts. Differences of the mortality pattern were observed also at state level and preserved across different sex and age groups while being largely independent of case numbers. Although Munich city had higher infection rates, more patients died during the first wave in Hamburg (OR 1.6, 95% CI 1.3-1.9). While the majority of Munich hospitals favoured a conservative management of hypoxemia including high flow nasal cannula (HFNC), Hamburg hospitals followed a more aggressive scheme of mechanical ventilation (MV). Austria and Switzerland experienced higher CFRs than Germany during the first wave but after changing treatment guidelines, both countries experienced lower CFRs during the second wave.

Conclusion: Different case fatality rates have been observed across Germany that are most likely caused by different treatment strategies.

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