Cardiovascular mortality in Brazil during the COVID-19 pandemic: a comparison between underlying and multiple causes of death

Abstract

ObjectivesThe COVID-19 pandemic has differentially impacted cardiovascular disease (CVD) mortality worldwide. Causes of death misclassification may be one of the reasons. We evaluated the impact of the pandemic on CVD mortality in Brazil, comparing underlying causes (UCs) and multiple causes (MCs) of death. Study designEcological time-series study. MethodsAn ecological, time-series study was conducted analysing age-standardised death rates for CVD, from epidemiological week (EW) 10/2020 to 39/2021, using data from the Mortality Information System, Brazil. CVD was defined using the International Classification of Diseases (ICD-10) coding, if reported as UC or MC of death. Observed and expected data (mean for the same EW, 2017–2019) were compared. Risk ratios (RiRs) were analysed, and 95% confidence intervals (CIs) were calculated. ResultsAge-standardised mortality rate for CVD as UC of death was 165.8 (95%CI: 165.4–166.3) per 100,000 inhabitants, similar to what was expected (165.6/100,000, 95%CI: 165.2–166.1, RiR = 1.00). There was increased out-of-hospital mortality (RiR = 1.18; 95%CI: 1.17–1.19) and deaths of ill-defined causes (RiR = 1.43; 95%CI: 1.42–1.44). The increase in out-of-hospital deaths was more pronounced in the North (RiR = 1.33; 95%CI 1.30–1.36) region, with a less resilient health system. Conversely, as MCs of death, there was a 10% increase in CVD mortality (observed: 243.2 [95%CI: 242.7–243.7], expected: 221.6 [95%CI: 221.1–222.1] per 100,000). An increase also occurred in the North and Central West regions (RiR = 1.16; 95%CI: 1.15–1.18), among men (RiR = 1.11; 95%CI: 1.11–1.12) and individuals aged ≥60 years (RiR = 1.11; 95%CI: 1.10–1.11). ConclusionsDuring the pandemic, mortality rates for CVD as MCs of death increased in Brazil, whereas as UC mortality rates did not change. Higher out-of-hospital mortality, misclassification, and competing causes of death may explain this pattern.