Socioeconomic markers of dengue mortality in the 100 Million Brazilian Cohort (2007–2018): A nationwide registry-based cohort study

Background: People living in economically disadvantaged circumstances experience higher risks of infections and death from arboviruses. However, more evidence is needed to better understand the socioeconomic factors influencing dengue mortality. We investigated if people of lower socioeconomic conditions in Brazil are more likely to die following dengue infection. Methodology/Principal Findings: Linking nationwide socioeconomic data from the 100 Million Brazilian Cohort with dengue disease and death records registered in Brazil between 1st January 2007 and 31st December 2018, we used multivariable hierarchical analysis to investigate the socioeconomic determinants of dengue-specific and all-cause mortality within 15 days of dengue symptom onset. Among the 3,018,131 individuals from the 100 Million Brazilian Cohort diagnosed with dengue, 1810 died from dengue (Case Fatality Rate (CFR)=0.06%, 95%CI = 0.06-0.06%) and 3076 (CFR = 0.10%, 95%CI = 0.10-0.11%) died from any cause within 15 days of dengue symptom onset. People residing in the Northeast (OR=2.32; 95%CI = 1.74-3.10) and Midwest (OR=1.68; 95%CI = 1.25-2.27) regions, self-identifying as black race/ethnicity (OR=1.58; 95%CI = 1.31-1.90), having lower level of education (OR=2.35, 95%CI = 1.17-4.73), being retired/receiving pension (OR=2.24; 95%CI = 1.76-2.86), living in a household with rudimentary sewage (OR=1.19; 95%CI = 1.04-1.37) and having >2 inhabitants per room (OR=1.31; 95%CI = 1.11-1.55) had at higher odds of dengue-specific mortality. Similar characteristics were also associated with higher all-cause mortality after dengue infection, but also included residing in North region (OR=1.60; 95%CI = 1.24-2.06) and rural areas (OR=1.12; 95%CI = 1.01-1.24), self-identifying as Asian (OR=1.65; 95%CI = 1.07-2.54) and mixed race/brown (OR=1.20; 95%CI = 1.10-1.31) and living in households with poorer quality building and sanitary conditions. Conclusions/Significance: Our findings provide evidence that individuals in Brazil with lower socioeconomic condition experience increased odds of dengue-specific and all-cause mortality within 15 days of dengue symptom onset. These findings underscore the importance of ensuring equitable access to high-quality treatment for severe dengue and suggest that reducing poverty and social inequality, including through improvement of sanitation and housing, may help mitigate dengue-related mortality. Author summary: Dengue fever disproportionately affects individuals living in economically disadvantaged areas. Using socioeconomic data from the 100 Million Brazilian Cohort linked to compulsory notification records for dengue and death certificates, this study investigates the socioeconomic factors associated with death following dengue cases in Brazil. We analysed over 3 million dengue cases reported between 2007 and 2018 and found that individuals from poorer regions, such as the Northeast, self-identifying as black race/ethnicity, with lower levels of education, and living in poor housing conditions, face higher chances of dying from dengue or from any cause within 15 days of symptom onset. These findings underscore that lower socioeconomic condition likely exacerbates the outcomes of dengue infection. Although further research is needed to understand the causal mechanisms including the role of co-morbidities, the findings of this study indicate that addressing poverty and inequality, improving sanitation and living conditions, and ensuring equitable access to high-quality healthcare may help to contribute to reducing dengue-related deaths.