All-Cause and Cause-Specific Excess Mortality During the First Two Years of the COVID-19 Pandemic in North-East of Iran: Reiterating the Significance of High-Quality Healthcare Systems.

Background: Excess mortality provides a comprehensive measure to assess the true impact of the disease on mortality rates. This study aimed to quantify excess mortality attributable to COVID-19 in northeastern Iran during the pandemic period (2020-2022).

Methods: This population-based cross-sectional study utilized population and mortality data extracted from electronic systems linked to Mashhad University of Medical Sciences (MUMS). Data analysis was conducted using R Version 4.3.3. A log-linear model was employed to predict expected deaths during the two-year pandemic period, incorporating predictor variables such as the year of interest, the presence of COVID-19, and the population size for each respective year. Excess deaths were calculated as the difference between the expected and observed mortality. Furthermore, by considering the confirmed deaths directly attributed to COVID-19 and the difference between these and the excess deaths, the number of indirect deaths during the pandemic was determined.

Results: The total count of recorded deaths from all causes exceeded the expected deaths by 31.15% (6750 cases) in the first year and 44.74% (10 078 cases) in the second year. The excess deaths were 1.48 and 1.79 times greater than the official reports of COVID-19 for the first and second years, respectively. It was also found that men experienced increased rates of excess deaths in each of the two years. Moreover, urban residents experienced higher rates of excess death in the same years. Based on cause-specific excess mortality, following infectious diseases, cardiovascular diseases (CVDs) accounted for the largest proportion of excess deaths in both years of the pandemic.

Conclusion: The overall mortality burden during the COVID-19 pandemic exceeded the official reports, highlighting the undercounting of the number of direct effects and emphasizing the significance of indirect effects. These findings underscore the importance of preparedness and organization of healthcare systems prior to a pandemic.