Global incidence, prevalence, years lived with disability (YLDs), disability-adjusted life-years (DALYs), and healthy life expectancy (HALE) for 371 diseases and injuries in 204 countries and territories and 811 subnational locations, 1990-2021: a systematic analysis for the Global Burden of Disease Study 2021

Abstract

Background Detailed, comprehensive, and timely reporting on population health by underlying causes of disability and premature death is crucial to understanding and responding to complex patterns of disease and injury burden over time and across age groups, sexes, and locations. The availability of disease burden estimates can promote evidence-based interventions that enable public health researchers, policy makers, and other professionals to implement strategies that can mitigate diseases. It can also facilitate more rigorous monitoring of progress towards national and international health targets, such as the Sustainable Development Goals. For three decades, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) has filled that need. A global network of collaborators contributed to the production of GBD 2021 by providing, reviewing, and analysing all available data. GBD estimates are updated routinely with additional data and refined analytical methods. GBD 2021 presents, for the first time, estimates of health loss due to the COVID-19 pandemic. Methods The GBD 2021 disease and injury burden analysis estimated years lived with disability (YLDs), years of life lost (YLLs), disability-adjusted life-years (DALYs), and healthy life expectancy (HALE) for 371 diseases and injuries using 100 983 data sources. Data were extracted from vital registration systems, verbal autopsies, censuses, household surveys, disease-specific registries, health service contact data, and other sources. YLDs were calculated by multiplying cause-age-sex-location-year-specific prevalence of sequelae by their respective disability weights, for each disease and injury. YLLs were calculated by multiplying cause-age-sex-location-year-specific deaths by the standard life expectancy at the age that death occurred. DALYs were calculated by summing YLDs and YLLs. HALE estimates were produced using YLDs per capita and age-specific mortality rates by location, age, sex, year, and cause. 95% uncertainty intervals (UIs) were generated for all final estimates as the 2 center dot 5th and 97 center dot 5th percentiles values of 500 draws. Uncertainty was propagated at each step of the estimation process. Counts and age-standardised rates were calculated globally, for seven super-regions, 21 regions, 204 countries and territories (including 21 countries with subnational locations), and 811 subnational locations, from 1990 to 2021. Here we report data for 2010 to 2021 to highlight trends in disease burden over the past decade and through the first 2 years of the COVID-19 pandemic. Findings Global DALYs increased from 2 center dot 63 billion (95% UI 2 center dot 44-2 center dot 85) in 2010 to 2 center dot 88 billion (2 center dot 64-3 center dot 15) in 2021 for all causes combined. Much of this increase in the number of DALYs was due to population growth and ageing, as indicated by a decrease in global age-standardised all-cause DALY rates of 14 center dot 2% (95% UI 10 center dot 7-17 center dot 3) between 2010 and 2019. Notably, however, this decrease in rates reversed during the first 2 years of the COVID-19 pandemic, with increases in global age-standardised all-cause DALY rates since 2019 of 4 center dot 1% (1 center dot 8-6 center dot 3) in 2020 and 7 center dot 2% (4 center dot 7-10 center dot 0) in 2021. In 2021, COVID-19 was the leading cause of DALYs globally (212 center dot 0 million [198 center dot 0-234 center dot 5] DALYs), followed by ischaemic heart disease (188 center dot 3 million [176 center dot 7-198 center dot 3]), neonatal disorders (186 center dot 3 million [162 center dot 3-214 center dot 9]), and stroke (160 center dot 4 million [148 center dot 0-171 center dot 7]). However, notable health gains were seen among other leading communicable, maternal, neonatal, and nutritional (CMNN) diseases. Globally between 2010 and 2021, the age-standardised DALY rates for HIV/AIDS decreased by 47 center dot 8% (43 center dot 3-51 center dot 7) and for diarrhoeal diseases decreased by 47 center dot 0% (39 center dot 9-52 center dot 9). Noncommunicable diseases contributed 1 center dot 73 billion (95% UI 1 center dot 54-1 center dot 94) DALYs in 2021, with a decrease in age-standardised DALY rates since 2010 of 6 center dot 4% (95% UI 3 center dot 5-9 center dot 5). Between 2010 and 2021, among the 25 leading Level 3 causes, agestandardised DALY rates increased most substantially for anxiety disorders (16 center dot 7% [14 center dot 0-19 center dot 8]), depressive disorders (16 center dot 4% [11 center dot 9-21 center dot 3]), and diabetes (14 center dot 0% [10 center dot 0-17 center dot 4]). Age-standardised DALY rates due to injuries decreased globally by 24 center dot 0% (20 center dot 7-27 center dot 2) between 2010 and 2021, although improvements were not uniform across locations, ages, and sexes. Globally, HALE at birth improved slightly, from 61 center dot 3 years (58 center dot 6-63 center dot 6) in 2010 to 62 center dot 2 years (59 center dot 4-64 center dot 7) in 2021. However, despite this overall increase, HALE decreased by 2 center dot 2% (1 center dot 6-2 center dot 9) between 2019 and 2021. Interpretation Putting the COVID-19 pandemic in the context of a mutually exclusive and collectively exhaustive list of causes of health loss is crucial to understanding its impact and ensuring that health funding and policy address needs at both local and global levels through cost-effective and evidence-based interventions. A global epidemiological transition remains underway. Our findings suggest that prioritising non-communicable disease prevention and treatment policies, as well as strengthening health systems, continues to be crucially important. The progress on reducing the burden of CMNN diseases must not stall; although global trends are improving, the burden of CMNN diseases remains unacceptably high. Evidence-based interventions will help save the lives of young children and mothers and improve the overall health and economic conditions of societies across the world. Governments and multilateral organisations should prioritise pandemic preparedness planning alongside efforts to reduce the burden of diseases and injuries that will strain resources in the coming decades.