Factors associated with mortality due to SARS-CoV-2 in the population over 75 years of age in the Community of Madrid()

OBJECTIVE: Various studies have identified factors associated with risk of mortality in patients with SARS-CoV-2 infection. However, their sample size has often been limited and their results partially contradictory. This study evaluated factors associated with COVID-19 mortality in the population of Madrid over 75 years of age, in infected patients, and in hospitalized patients up to January 2021. PATIENTS AND METHODS: This population-based cohort study analyzed all residents of the Community of Madrid born before January 1, 1945 who were alive as of December 31, 2019. Demographic and clinical data were obtained from primary care electronic medical records (PC-Madrid), data on hospital admissions from the Conjunto Mínimo Básico de Datos (CMBD, Minimum Data Set), and data on mortality from the Índice Nacional de Defunciones (INDEF, National Death Index). Data on SARS-CoV-2 infection, hospitalization, and death were collected from March 1, 2020 to January 31, 2021. RESULTS: A total of 587,603 subjects were included in the cohort. Of them, 41,603 (7.1%) had confirmed SARS-CoV-2 infection, of which 22,362 (53.7% of the infected individuals) were hospitalized and 11,251 (27%) died. Male sex and age were the factors most closely associated with mortality, though many comorbidities also had an influence. The associations were stronger in the analysis of the total population than in the analysis of infected or hospitalized patients. Mortality among hospitalized patients was lower during the second wave (33.4%) than during the first wave (41.2%) of the pandemic. CONCLUSION: Age, sex, and numerous comorbidities are associated with risk of death due to COVID-19. Mortality in hospitalized patients declined notably after the first wave of the pandemic.