The proportion of COVID-19 deaths in central Europe in 2020 and 2021 would have been up to 18% to 27% higher if death certificates listing the virus as a contributing condition had coded it as the cause of death, estimates a new study published in PLOS One.
University of Warsaw-led researchers examined 187,300 death certificates from Austria, Bavaria (Germany), Czechia (Czech Republic), Lithuania, and Poland mentioning COVID-19 in 2020 and 2021. They performed a two-step analysis of cause-of-death association indicators (CDAIs) and contributing CDAIs to estimate the statistical strength of associations between COVID-19 and other conditions.
“Excess deaths reported to causes other than COVID-19 may have been due to unrecognised coronavirus disease, the interruptions in care in the overwhelmed health care facilities, or socioeconomic effects of the pandemic and lockdowns,” the authors noted. “Death certificates provide exhaustive medical information, allowing us to assess the extent of unrecognised COVID-19 deaths.”
Many possible reasons for undercount
A total of 15,700 death certificates listed COVID-19 as a contributing condition, and three of four recorded a statistically significant COVID-19 complication or pre-existing condition as the cause.
Unrecognised coronavirus deaths were equivalent to the entire surplus of excess mortality beyond registered COVID-19 deaths in Austria and the Czech Republic, and its large proportion (25–31%) in Lithuania and Bavaria.
“In Austria, Bavaria, Czechia, and Lithuania the scale of COVID-19 mortality would have been up to 18–27% higher had COVID-19 been coded as the underlying cause of death,” the researchers wrote. “Unrecognised coronavirus deaths were equivalent to the entire surplus of excess mortality beyond registered COVID-19 deaths in Austria and the Czech Republic, and its large proportion (25–31%) in Lithuania and Bavaria.”
The undercount may be attributable to a lack of COVID-19 testing, atypical disease course, misclassification, or deaths from other causes such as cardiovascular disease and cancers that may have risen as strained healthcare systems prioritized COVID-19 patients or fallen owing to the reduction of risk factors such as air pollution, traffic, or other infectious diseases.
“Finally, mortality may have increased due to harmful behaviours typical of the socioeconomic instability experienced by some groups during the pandemics, lockdowns and economic slowdown, such as abuse of noxious substances, suicides and accidents,” the researchers wrote.
