The Importance of Cause-of-Death Certification for the COVID-19 Burden Assessment: the Case of Central Europe

Background: In Central Europe, the increase in mortality during the COVID-19 pandemic exceeded the number of deaths registered due to coronavirus disease. Miscertification of COVID-19 has been suggested as one of the possible explanations. Analysis of all mentions from death certificates allows us to identify cases where COVID-19 was reported as a contributing rather than the underlying cause of death (UCoD). Methods: Analysis of 187,000 death certificates with a COVID-19 mention from Austria, Bavaria, Czechia, Lithuania and Poland, 2020–2021. Cause of Death Association Indicators (CDAIs) and Contributing CDAIs were calculated to identify and measure the strength of associations between COVID-19, reported as UCoD or not, and all other medical mentions. Results: Death certificates reporting COVID-19 included on average more medical information than other death certificates. In 171,600 deaths with COVID-19 as the UCoD, ten groups of comorbidities and ten types of complications revealed significant and strong association with COVID-19. Further 15,700 deaths were certified with COVID-19 only as a contributing condition, of which almost 20% were assigned to typical coronavirus complications, such as cerebral infarction, Acute Myocardial Infarction, renal failure. In Austria, Bavaria, Czechia and Lithuania the reported scale of COVID-19 mortality would have been 18-27% higher had COVID-19 been coded as the UCoD in all the cases. Conclusions: Complete death certificate information allows us to assess the scale of COVID-19 miscertification and the burden of COVID-19. Deaths registered with a coronavirus comorbidity were equivalent to the total estimated excess mortality in Austria and Czech Republic, and its large proportion in Lithuania and Bavaria.