Previous studies of excess deaths (the gap between observed and expected deaths) during the coronavirus disease 2019 (COVID-19) pandemic found that publicly reported COVID-19 deaths underestimated the full death toll, which includes documented and undocumented deaths from the virus and non–COVID-19 deaths caused by disruptions from the pandemic.1,2 A previous analysis found that COVID-19 was cited in only 65% of excess deaths in the first weeks of the pandemic (March-April 2020); deaths from non–COVID-19 causes (eg, Alzheimer disease, diabetes, heart disease) increased sharply in 5 states with the most COVID-19 deaths.1 This study updates through August 1, 2020, the estimate of excess deaths and explores temporal relationships with state reopenings (lifting of coronavirus restrictions).
Death data for 2014-2020 and population counts for the 50 states and the District of Columbia were obtained from the National Center for Health Statistics3,4 and US Census Bureau,5 respectively. Death counts from March 1, 2020, through August 1, 2020, were taken from provisional, unweighted data released on September 9, 2020.3 Connecticut and North Carolina were excluded due to missing data. A hierarchical Poisson regression model, described elsewhere,1 was used to predict expected deaths based on historic norms. COVID-19 deaths included those in which COVID-19 was cited as an underlying or contributing cause. Data for deaths not attributed to COVID-19 were only available for underlying causes of death, including Alzheimer disease, heart disease, and 10 other grouped causes, defined elsewhere.1 Reopening dates were obtained from the New York Times.6
To confirm the validity of observed increases in non–COVID-19 deaths, the Joinpoint regression program (version 4.8.0.1; Statistical Research and Applications Branch, National Cancer Institute) was used to specify the weeks (joinpoints) when slopes changed (as measured by the annual percentage change [APC]) and their statistical significance (2-sided test, .05 threshold). To estimate dispersion in the epidemic curve for each state, the number of consecutive weeks during which 90% of excess deaths occurred (ED90) was calculated. All calculations were performed in SAS (version 9.4; SAS Institute) and R (version 3.6.1; The R Foundation).
Between March 1 and August 1, 2020, 1 336 561 deaths occurred in the US, a 20% increase over expected deaths (1 111 031 [95% CI, 1 110 364 to 1 111 697]). The 10 states with the highest per capita rate of excess deaths were New York, New Jersey, Massachusetts, Louisiana, Arizona, Mississippi, Maryland, Delaware, Rhode Island, and Michigan. The states with the highest per capita rate of excess deaths changed from week to week (Video). The increase in absolute deaths in these states relative to expected values ranged from 22% in Rhode Island and Michigan to 65% in New York (Table). Three states with the highest death rates (New Jersey, New York, and Massachusetts) accounted for 30% of US excess deaths but had the shortest epidemics (ED90 < 10 weeks). States that experienced acute surges in April (and reopened later) had shorter epidemics that returned to baseline in May, whereas states that reopened earlier experienced more protracted increases in excess deaths that extended into the summer (Figure).
Of the 225 530 excess deaths, 150 541 (67%) were attributed to COVID-19. Joinpoint analyses revealed an increase in deaths attributed to causes other than COVID-19, with 2 reaching statistical significance. US mortality rates for heart disease increased between weeks ending March 21 and April 11 (APC, 5.1 [95% CI, 0.2-10.2]), driven by the spring surge in COVID-19 cases. Mortality rates for Alzheimer disease/dementia increased twice, between weeks ending March 21 and April 11 (APC, 7.3 [95% CI, 2.9-11.8]) and between weeks ending June 6 and July 25 (APC, 1.5 [95% CI, 0.8-2.3]), the latter coinciding with the summer surge in sunbelt states.
Although total US death counts are remarkably consistent from year to year, US deaths increased by 20% during March-July 2020. COVID-19 was a documented cause of only 67% of these excess deaths. Some states had greater difficulty than others in containing community spread, causing protracted elevations in excess deaths that extended into the summer. US deaths attributed to some noninfectious causes increased during COVID-19 surges. Excess deaths attributed to causes other than COVID-19 could reflect deaths from unrecognized or undocumented infection with severe acute respiratory syndrome coronavirus 2 or deaths among uninfected patients resulting from disruptions produced by the pandemic. Study limitations include the reliance on provisional data, inaccuracies in death certificates, and assumptions applied to the model.
Accepted for Publication: September 15, 2020.
Corresponding Author: Steven H. Woolf, MD, MPH, Center on Society and Health, Department of Family Medicine and Population Health, Virginia Commonwealth University School of Medicine, 830 E Main St, Ste 5035, Richmond, VA 23298-0212 (steven.woolf@vcuhealth.org).
Published Online: October 12, 2020. doi:10.1001/jama.2020.19545
Author Contributions: Drs Woolf and Chapman had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
Concept and design: Woolf, Chapman, Sabo, Weinberger.
Acquisition, analysis, or interpretation of data: All authors.
Drafting of the manuscript: Woolf, Sabo.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: All authors.
Administrative, technical, or material support: Chapman.
Supervision: Woolf, Chapman.
Conflict of Interest Disclosures: Dr Weinberger reported receiving personal fees from Pfizer, Merck, Affinivax, and GlaxoSmithKline outside the submitted work and being the principal investigator for a research grant from Pfizer to Yale University. No other disclosures were reported.
Funding/Support: Drs Woolf and Chapman and Ms Hill received partial funding from grant UL1TR002649 from the National Center for Advancing Translational Sciences. Drs Woolf and Chapman also received partial funding from grant R01AG055481 from the National Institute on Aging. Dr Weinberger was funded by grant R01AI137093 from the National Institute of Allergy and Infectious Diseases.
Role of the Funder/Sponsor: The funders had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.
Additional Contributions: We thank Cassandra Ellison, MFA, art director for the Virginia Commonwealth University Center on Society and Health, for her assistance with graphic design; she was not compensated beyond her salary.