Multiple cause of death during the COVID-19 pandemic: a population study In Colombia and Brazil

Objectives: To assess differences in age-standardized disease-specific mortality rates derived from the underlying cause of death (UCOD) versus multiple cause of death (MCOD) data in two Latin American countries during the COVID-19 pandemic. Methods: Using all death certificates for residents of Brazil (n = 6,207,785) and Colombia (n = 1,180,880) from 2019 through 2022, we extracted UCOD and all contributing causes, assigned weights (50% to UCOD, remainder equally among contributing causes), and calculated annual age- and sex-standardized mortality rates for neoplasms, circulatory diseases, diabetes mellitus (DM), and non-COVID communicable diseases. We then computed rate differences and rate ratios contrasting MCOD with UCOD estimates. Results: MCOD-DM mortality exceeded UCOD by up to 70%. In Colombia, MCOD-CVD surpassed UCOD during 2020-2021, corresponding to approximately 1,950 extra male and 1,560 extra female CVD deaths in 2021. Discrepancies for neoplasms and other communicable diseases were smaller and stable. Conclusion: These findings demonstrate that MCOD methods reveal substantial underestimation of diabetes- and cardiovascular-related mortality, underscoring the value of MCOD surveillance for public health planning.