Sociodemographic inequalities and excess non-COVID-19 mortality during the COVID-19 pandemic: A data-driven analysis of 1,069,174 death certificates in Mexico

ABSTRACT

BACKGROUNDIn 2020, Mexico experienced one of the highest rates of excess mortality globally. However, the extent to which non-COVID deaths contributed to excess mortality, its regional characterization, and the association between municipal-and individual-level sociodemographic inequality has not been characterized. METHODSWe conducted a retrospective municipal an individual-level study using death certificate data in Mexico from 2016-2020. We analyzed mortality related to COVID-19 and to non-COVID-19 causes using ICD-10 codes to identify cause-specific mortality. Excess mortality was estimated as the increase in deaths in 2020 compared to the average of 2016-2019, disaggregated by primary cause of death, death setting (in-hospital and out-of-hospital) and geographical location. We evaluated correlates of non-COVID-19 mortality at the individual level using mixed effects logistic regression and correlates of non-COVID-19 excess mortality in 2020 at the municipal level using negative binomial regression. RESULTSWe identified 1,069,174 deaths in 2020 (833.5 per 100,000 inhabitants), which was 49% higher compared to the 2016-2019 average (557.38 per 100,000 inhabitants). Overall excess mortality (276.11 deaths per 100,000 inhabitants) was attributable in 76.1% to COVID-19; however, non-COVID-19 causes comprised one-fifth of excess deaths. COVID-19 deaths occurred primarily in-hospital, while excess non-COVID-19 deaths decreased in this setting and increased out-of-hospital. Excess non-COVID-19 mortality displayed geographical heterogeneity linked to sociodemographic inequalities with clustering in states in southern Mexico. Municipal-level predictors of non-COVID-19 excess mortality included levels of social security coverage, higher rates of COVID-19 hospitalization, and social marginalization. At the individual level, lower educational attainment, blue collar workers, and lack of medical care assistance were associated with non-COVID-19 mortality during 2020. CONCLUSIONNon-COVID-19 causes of death, largely chronic cardiometabolic conditions, comprised up to one-fifth of excess deaths in Mexico during 2020. Non-COVID-19 excess deaths occurred disproportionately out-of-hospital and were associated with both individual-and municipal-level sociodemographic inequalities. These findings should prompt an urgent call to action to improve healthcare coverage and access to reduce health and sociodemographic inequalities in Mexico to reduce preventable mortality in situations which increase the stress of healthcare systems, including the ongoing COVID-19 pandemic.