Trends and cross-country inequities by region, sex, age in the mortality, incidence, and disability-adjusted life years of COVID-19: Analysis from the Global Burden of Disease Study 2021

Background: The coronavirus disease 2019 (COVID-19) pandemic has imposed a substantial disease burden globally and has further exacerbated pre-existing health inequities. This study aimed to provide a comprehensive assessment of the burden and inequities associated with COVID-19 across diverse populations. Methods: Using data from the Global Burden of Disease 2021, we systematically analyzed deaths, incidence, disability-adjusted life years (DALYs), and years of life lost (YLLs) of COVID-19 stratified by sex, age, and region. The temporal trends pre- and post-2019 (i.e., 1990–2019 and 2019–2021) were measured using average annual percent change (AAPC). Additionally, the cross-country absolute and relative sociodemographic index (SDI)-related health inequities were assessed using the slope index and concentration index, respectively. The SDI is a composite development indicator that incorporates income, educational attainment, and fertility conditions. Results: Trends in the global burden of all-cause mortality and DALYs exhibited significant declines (AAPC 0) following the COVID-19 pandemic. In 2021, COVID-19 resulted in 2.28 billion incident cases and 7.89 million deaths globally, with an age-standardized DALYs rate of 2,501 per 100,000 population. While incidence rates were relatively evenly distributed across populations, mortality was disproportionately higher among males and older adults. Substantial health inequities in the burden of COVID-19 were evident across 204 countries and territories, with absolute widening inequities notably in 2021 (e.g., the slope index of inequity for DALYs rose from 2,713 in 2020 to 4,044 in 2021). Greater inequities are disproportionately concentrated among males, middle-aged and older individuals, and regions with lower SDI levels. Conclusions: These findings highlight the substantial disease burden of COVID-19 and elucidate the multidimensional health inequities exacerbated by the pandemic, providing crucial evidence for targeted interventions to address inequities and strengthen resilience in future global health emergencies. Author summary: The coronavirus disease 2019 (COVID-19) pandemic has imposed a substantial disease burden globally in recent years. Evaluating health inequities associated with COVID-19 is essential for strengthening the current healthcare system and guiding public health policy priorities to inform future global health emergencies. We found that the all-cause disease burden had significantly declined prior to the COVID-19 pandemic but subsequently reversed due to the substantial impact of COVID-19, resulting in an upward trend from 2019 to 2021. Although the incidence of COVID-19 was relatively consistent across sex and age groups, mortality and disability-adjusted life years were markedly higher among males and older people. Substantial absolute and relative inequities associated with the sociodemographic index were observed in the burden of COVID-19 across 204 countries and territories, with these inequities further widening in 2021. Furthermore, greater health inequities were disproportionately observed among males, middle-aged and older populations, and regions with a lower sociodemographic index. These findings underscore the profound global impact of COVID-19 and its associated health inequities across multiple dimensions, highlighting the critical need for targeted public health interventions to mitigate inequities and strengthen the resilience of health systems in anticipation of future global health emergencies.