Bilinski and Emanuel (2020) sought to understand to what extent U.S. mortality was driven by the early surge of cases prior to improvements in prevention and patient management vs. a poor longer-term response. The researchers compared U.S. COVID-19 deaths and excess all-cause mortality in 2020 (vs 2015-2019) to that of 18 countries with diverse COVID-19 responses.

The investigators compared the U.S. to Organization for Economic Co-operation and Development countries with populations exceeding 5 million and greater than $25 000 per capita gross domestic product. For each country, they calculated the COVID-19 per capita mortality rate and grouped countries by mortality: (1) low (COVID-19 deaths, <5/100 000), (2) moderate (5-25/100 000), and (3) high (>25/100 000). They used Poisson regression for comparisons across countries. They calculated the difference in COVID-19 deaths between each country and the U.S. through Sept. 19, 2020 (week 38) under three scenarios: if the U.S. had a comparable per capita COVID-19 mortality rate to each country from the start of the pandemic (February 13) or if the U.S. mortality rate became comparable to other countries beginning May 10 or June 7, to allow lag time for policy interventions.

They also considered all-cause mortality per capita for countries with publicly available data through July 25, 2020 (week 30) and they note that this measure is robust to country-level differences in COVID-19 death coding and captures indirect pandemic effects. We estimated excess all-cause mortality (the difference between mean 2020 deaths and deaths in corresponding weeks of 2015-2019) for each country and the U.S., compared rates across countries using Poisson regression with country and week fixed effects, and estimated the difference in excess all-cause mortality between each country and the U.S. as described above.

On Sept. 19, 2020, the U.S. reported a total of 198,589 COVID-19 deaths (60.3/100,000), higher than countries with low and moderate COVID-19 mortality but comparable with high-mortality countries. For instance, Australia (low mortality) had 3.3 deaths per 100,000 and Canada (moderate mortality) had 24.6 per 100,000. Conversely, Italy had 59.1 COVID-19 deaths per 100,000; Belgium had 86.8 per 100,000. If the U.S. death rates were comparable to Australia, the U.S. would have had 187.661 fewer COVID-19 deaths (94% of reported deaths), and if comparable with Canada, 117,622 fewer deaths (59%).

The researchers note, "While the U.S. had a lower COVID-19 mortality rate than high-mortality countries during the early spring, after May 10, all 6 high-mortality countries had fewer deaths per 100,000 than the U.S. For instance, between May 10 and Sept. 19, 2020, Italy’s death rate was 9.1/100,000 while the U.S.’s rate was 36.9/100 000. If the US had comparable death rates with most high-mortality countries beginning May 10, it would have had 44 210 to 104,177 fewer deaths (22%-52%). If the US had comparable death rates beginning June 7, it would have had 28% to 43% fewer reported deaths (as a percentage overall). In the 14 countries with all-cause mortality data, the patterns found for COVID-19–specific deaths were similar for excess all-cause mortality. In countries with moderate COVID-19 mortality, excess all-cause mortality remained negligible throughout the pandemic. In countries with high COVID-19 mortality, excess all-cause mortality reached as high as 102.1/100 000 in Spain, while in the U.S. it was 71.6/100,000. However, since May 10 and June 7, excess all-cause mortality was higher in the U.S. than in all high-mortality countries."

Reference: Bilinski A and Emanuel EJ. COVID-19 and Excess All-Cause Mortality in the US and 18 Comparison Countries. JAMA. Published online Oct. 12, 2020. doi:10.1001/jama.2020.20717