Disease-specific Excess Mortality During the COVID-19 Pandemic

An Analysis of Weekly US Death Data for 2020

Dongshan Zhu, PhD; Akihiko Ozaki, PhD; Salim S. Virani, PhD

Disclosures

Am J Public Health. 2021;111(8):1518-1522. 

In This Article

Discussion

Prior studies have shown that the severity of the COVID-19 pandemic is associated with the adoption of stringent measures as a response to the pandemic.[10] These measures can have an impact on access to and provision of services, and may increase vulnerability to poor outcomes among people with comorbid conditions. In the United States, the Department of Veterans Affairs reported that the number of inpatients for 6 potentially life-threatening diseases (including myocardial infarction and stroke) declined by 41.9% in the first week of the pandemic.[11] Also, one third or more of excess deaths were not related to COVID-19, but were from heart diseases, diabetes, and CVD.[4,12] Our study found that after week 11 (March 8–14, the beginning of the spread in the United States), excess deaths from CVD, diabetes, influenza, and respiratory diseases started to increase. The trajectories of excess deaths from CVD were highly in line with the trajectories of excess deaths related to COVID-19, either at the national level or in the 4 states.

The increased excess deaths from CVD and diabetes might be from several sources. First, in the early stage of the pandemic (before week 11), laboratory-confirmed cases only accounted for a small percentage of total cases.[13] Deaths from COVID-19 in the early-spread stage might have been classified as deaths from other diseases. Especially in elderly people, who are usually comorbid with multiple chronic diseases (e.g., CVD), deaths from COVID-19 in the early stage might have been classified as deaths from CVD. Our findings also support this misclassification in the early stage. In the national-level trajectories and in the trajectories of Florida and Texas, we found that the rise of excess deaths from CVD started earlier than the rise of excess deaths related to COVID-19. Second, there were deaths that might have been caused by COVID-19 but were not ascertained. For example, people with COVID-19 who died at home or in nursing homes without being tested for COVID-19 might have been coded into other groups. Third, increased excess mortality from NCD might have been caused by disrupted or reduced services. As the pandemic continues, health care systems must balance the need to provide necessary services with minimizing the risk to patients and health care personnel. The reduction or disruption of services for screening and diagnosing NCDs, and patients' aversion to hospital visits, may have resulted in some patients dying from NCDs (e.g., acute myocardial infraction), whether or not they were diagnosed. This also explains why the trajectory of unclassified deaths increased at the national level: patients who died of NCDs without being diagnosed would be coded into unclassified. It is hard to determine how much each of these causes contributed to excess CVD deaths. This shows the challenges in quantifying excess deaths in the COVID-19 pandemic until more reliable data are available.

The full impact on excess mortality of the COVID-19 pandemic—and of the restrictions adopted to mitigate the risk of its spread—is yet to be fully understood. Because the 4 states all adopted the same measures at around the same time, the states' different trajectories may be mostly a result of the relative severity of the COVID-19 pandemic in each state. In the United States, the increasing excess deaths from CVD may indicate that the health service was disrupted during the pandemic. Globally, 58% of countries have adopted alternative strategies for continuing health services and 70% of countries have started collecting NCD data among COVID-19 patients.[14]

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