COVID-19 cases and monthly all-cause, cancer, CVD and diabetes mortality in 16 countries, 2020-2021

Background The COVID-19 pandemic has been associated with increased mortality from various chronic diseases. This study evaluates the monthly excess mortality from all causes, cancer, cardiovascular disease (CVD), and diabetes during 2020 and 2021, examining its correlation with COVID-19 cases. Methods Monthly cause-specific mortality data were obtained from national statistical offices' public repositories or obtained directly from them upon request. Population data were obtained from the United Nations archives. Excess deaths were calculated as the difference between observed and expected deaths, with expected deaths for 2020 and 2021 estimated using a quasi-Poisson regression model fitted on 2010-2019 data (or a shorter available period). The correlation between COVID-19 cases and monthly excess mortality was quantified using Spearman's correlation coefficient (r). Results The study included 16 countries (Argentina, Austria, Brazil, Switzerland, Chile, Czech Republic, Germany, Georgia, Hungary, Italy, Latvia, Lithuania, Mexico, Serbia, Slovakia, and the USA). A positive correlation between COVID-19 cases and monthly excess mortality was observed for all causes in all countries (r: 0.61 to 0.91), for CVD in 11 countries (r: 0.45 to 0.85), and for diabetes in 13 countries (r: 0.42 to 0.79). Excess mortality above 5% was identified for all causes in 14 countries in both 2020 and 2021, for CVD in seven countries in 2020 and nine in 2021, and for diabetes in 10 countries in 2020 and 11 in 2021. No significant excess cancer mortality was observed. Conclusions Excess mortality from CVD and diabetes persisted through 2021 in several countries, aligning with COVID-19 peaks and indicating a short-term impact of the pandemic on mortality from vascular and metabolic diseases but not cancer.