Causes of excess deaths in the US relative to other wealthy nations, 1999-2020: a population autopsy

Importance: The US has higher mortality rates than other wealthy nations. Objective: To determine causes of death responsible for excess mortality in the US compared to other wealthy nations and how the causes involved in this survival gap have changed over time. Design: Repeat cross-sectional study, 1999 to 2020. Setting: United States and 12 other wealthy nations. Participants: All residents. Exposures: Residing in the US versus other wealthy nations. Main outcome and measures: Excess US mortality in each year due to specific causes of death using data from the World Health Organization Mortality Database. Differences between the US and other wealthy nations were quantified for each cause of death as: (1) the number of excess US deaths (i.e., deaths that would have been averted if US death rates equaled the average rates of other wealthy nations); (2) years of life lost (YLL) resulting from excess US deaths; and (3) the ratio of observed deaths to expected deaths if US mortality rates equaled the average of other wealthy nations. Results: 10,856,851 excess US deaths occurred between 1999 and 2020. In 2019, prior to the COVID-19 pandemic, there were 637,682 excess US deaths, with leading causes including circulatory diseases (41% of total), mental and nervous system disorders (25%), diabetes, renal, and metabolic diseases (15%), drug poisonings, alcohol-related deaths, and suicide (13%), respiratory disease (12%), and transportation accidents (5%). Over two decades, excess US deaths due to drug poisonings, alcohol and suicide increased from -5,937 in 1999 to 109,015 in 2020. In 2019, deaths from drug poisonings were 6.7 times higher in the US than in peer countries. Circulatory mortality accounted for the largest absolute number of excess US deaths in nearly every year. In 2020, one in 5 excess US deaths were attributed to COVID-19. Conclusions and Relevance: The US had substantially higher death rates than other wealthy nations between 1999 and 2020, despite having similar access to advanced medical technology. Many of these excess US deaths could likely be avoided by adopting health and social policies that have benefited peer countries.