Excess Mortality From Non–COVID-19 Causes During the COVID-19 Pandemic in Philadelphia, Pennsylvania, 2020–2021

Abstract

Objectives. To estimate excess mortality from non–COVID-19 causes during the COVID-19 pandemic in Philadelphia, Pennsylvania, and understand disparities by race/ethnicity, age, and sex.

Methods. We used Poisson regression models of weekly deaths using data from Pennsylvania’s vital registration system (2018–2021).

Results. There was significant excess mortality as a result of heart disease, homicide, diabetes, drug overdoses, traffic crashes, and falls in 2020–2021; the burden of this excess non–COVID-19 mortality fell on non-Hispanic Black Philadelphians. Among younger non-Hispanic Black men, homicide and drug overdoses were responsible for 54% and 18% of excess deaths—more than COVID-19 (17%). For younger non-Hispanic Black women, drug overdoses accounted for 51% of excess deaths, whereas COVID-19 accounted for 40%.

Conclusions. Excess mortality was not solely caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; the causative agent of COVID-19), particularly at younger ages. Indirect pandemic mortality exacerbated prepandemic disparities by race/ethnicity.

Public Health Implications. Excess mortality as a result of non–COVID-19 causes may reflect indirect pandemic mortality. National cause-of-death data lag behind local cause-of-death data; local data should be examined as an early indication of trends and disparities. Public health practitioners must center health equity in pandemic response and planning. (Am J Public Health. 2022;112(12):1800–1803. https://doi.org/10.2105/AJPH.2022.307096)

The COVID-19 pandemic caused a dramatic increase in mortality, but not all of this excess mortality is directly attributable to infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; the causative agent of COVID-19).¹ The pandemic caused profound disruptions in society, which may have led to excess mortality indirectly related to the virus. Researchers have speculated about these indirect pathways—such as interruptions in health care^2,3 and worsening mental health⁴—but so far, little work has studied excess mortality as a result of non–COVID-19 causes.

In this study, we estimated excess mortality as a result of non–COVID-19 causes of death in Philadelphia, Pennsylvania. Past studies have documented differences in COVID-19 mortality by sex,⁵ age,⁶ and race/ethnicity^7,8; we therefore compared mortality by these demographic characteristics to see if this was also the case for non–COVID-19 mortality. National cause-of-death data lag behind local cause-of-death data; these data from Philadelphia—the sixth largest US city—provide a timely estimate of trends and disparities in mortality for 2020–2021.

METHODS

Data are from Pennsylvania’s vital registration system. We used final 2018–2019 death files, combined with preliminary 2020–2021 files (updated June 30, 2022), to examine mortality in Philadelphia from January 1, 2018, to January 1, 2022. Deaths are reported with a delay; for more details, see section 1 of Appendix (available as a supplement to the online version of this article at http://www.ajph.org). We calculated excess mortality rates with denominators from the US Census Bureau’s 2021 Annual County Resident Population Estimates.

Following Todd et al.,⁹ we trained Poisson models of weekly mortality on 2018–2019 data, stratified by age, sex, and race/ethnicity and allowing for seasonal trends. Our past work examined all-cause mortality through 2020⁹; here, we added cause-specific mortality from the most common pre-COVID-19 causes of death (heart disease, cancer, injury [disaggregated into homicide, drug overdoses, traffic crashes, and falls], cerebrovascular disease, diabetes, septicemia, influenza and pneumonia, chronic respiratory diseases, and chronic kidney diseases) and data through 2021. (See section 2 of online Appendix for model details.) We then used these models to estimate expected cause-specific mortality from March 15, 2020, to January 1, 2022 by sex (male, female), age group (< 50 years old, ≥ 50 years), and race/ethnicity (non-Hispanic Black, non-Hispanic White; other categories omitted because of small counts). We compared expectations with observed deaths to obtain estimates of cause-specific excess mortality. All deaths as a result of COVID-19 were considered excess deaths. We conducted the analysis using R 4.1.1 (R Foundation for Statistical Computing, Vienna, Austria).

RESULTS

There were 5963 excess deaths from all causes between March 15, 2020, and January 1, 2022, representing 23% more deaths than predicted (Table A, available as a supplement to the online version of this article at http://www.ajph.org); 4469 (75%) of these excess deaths were directly attributable to COVID-19. Among non–COVID-19 causes of death, the greatest proportional increases above expectations occurred for deaths caused by traffic crashes (53% more deaths than expected), homicide (51%), and diabetes (41%). Significant increases above expectations were also observed for deaths caused by falls (22%), drug overdoses (16%), and heart disease (6%). As the most common cause of death, heart disease was responsible for the largest number of excess deaths (n = 375) of any non–COVID-19 cause, despite only a modest percentage increase. Homicide was responsible for the second largest number of excess deaths (n = 327), followed by drug overdose (n = 272) and diabetes (n = 244). As less common causes of death, traffic crashes and falls accounted for 95 and 53 excess deaths, respectively. There was a decrease below expectations for deaths from chronic respiratory diseases (9%, or 89 fewer than expected). Observed deaths were not significantly different from expectations for cancer, kidney disease, pneumonia and influenza, stroke, or septicemia.

Excess mortality was not distributed equally; the burden fell more heavily on non-Hispanic Black Philadelphians than non-Hispanic White Philadelphians. Figure A (available as a supplement to the online version of this article at http://www.ajph.org) shows excess deaths per 100 000 from all causes by sex, age group, and race/ethnicity. There was significant excess mortality among adults aged 50 years and older in all sex–race groups. However, at younger ages, only non-Hispanic Black men and women experienced excess mortality (241 and 70 excess deaths per 100 000, respectively), whereas non-Hispanic White women and men did not experience significant excess mortality.

Figure 1 disaggregates excess mortality for age–sex–race/ethnicity groups by cause. Only causes of death for which the number of deaths was significantly different from expectations are labeled; see Table B (available as a supplement to the online version of this article at http://www.ajph.org) for complete counts. For those aged 50 years and older, COVID-19 was overwhelmingly responsible for excess mortality: there were 1142 COVID-19 deaths per 100 000 for older non-Hispanic Black men (representing 66% of excess deaths for this group), 859 per 100 000 for older non-Hispanic Black women (79% of excess deaths), 855 per 100 000 for older non-Hispanic White men (97%), and 661 per 100 000 for older non-Hispanic White women (over 100%, a figure that might be attributable to declines from other causes). For older non-Hispanic Black men, there was significant excess mortality from heart disease, drug overdoses, diabetes, and traffic crashes. Among older non-Hispanic Black women, mortality from heart disease and drug overdoses significantly exceeded expectations. For older non-Hispanic White men, diabetes was the only significant non–COVID-19 contribution to excess mortality. Older non-Hispanic White women also experienced significant excess mortality from diabetes, but this was more than offset by significant reductions in mortality from chronic respiratory diseases, possibly because of COVID-19 mitigation strategies like social distancing and masking.

FIGURE 1—

Excess Mortality per 100 000 Population by Cause of Death, Race/Ethnicity, and Sex for Those Aged (a) Younger than 50 Years and (b) 50 Years or Older: Philadelphia, PA, March 15, 2020–January 1, 2022

Note. NH = non-Hispanic; “sup.” indicates suppressed value because observed count was less than 10. We calculated COVID-19 mortality rates assuming that (expected deaths) = 0.

*P < .05, **P < .01 for test of the null hypothesis that (observed deaths) = (expected deaths).

For Philadelphians aged younger than 50 years, the contribution of COVID-19 to excess mortality was far more modest. Among young non-Hispanic Black men, COVID-19 was only the third leading cause of excess mortality (40 excess deaths per 100 000; 17% of excess deaths), trailing behind homicide (131 per 100 000; 54%) and drug overdoses (45 per 100 000; 18%). Traffic crashes also significantly contributed to excess mortality for young non-Hispanic Black men. For young non-Hispanic Black women, drug overdoses contributed more to excess mortality (35 per 100 000; 51% of excess deaths) than COVID-19 (28 per 100 000; 40%). There was no significant all-cause excess mortality among young non-Hispanic White men and women; excess COVID-19 deaths were offset by lower-than-expected mortality from drug overdoses and heart disease.

DISCUSSION

This study estimated cause-specific excess mortality during the COVID-19 pandemic in Philadelphia. In addition to deaths from COVID-19, there was significant excess mortality from heart disease, homicide, diabetes, drug overdoses, traffic crashes, and falls. The burden of non–COVID-19 mortality disproportionately affected older non-Hispanic Black Philadelphians compared with older non-Hispanic White Philadelphians. Among younger non-Hispanic Black Philadelphians, COVID-19 mortality was dwarfed by excess mortality from homicide and drug overdoses. Excess non–COVID-19 mortality may have resulted from interruptions in health care (for heart disease, diabetes, and drug overdoses), or from stress, anxiety, and mental strain (all causes). Although the number of traffic crashes in Philadelphia decreased in the first year of the pandemic, the number of fatalities increased, possibly because of excess speed amid reduced traffic volume.¹⁰ Although more research is needed to understand why non–COVID-19 causes of death contributed to excess mortality during the pandemic, our work shows that this excess mortality was substantial, and contributed to mortality disparities by race/ethnicity.

PUBLIC HEALTH IMPLICATIONS

Preexisting racial mortality disparities were exacerbated by COVID-19.⁷ This study is preliminary evidence that non–COVID-19 mortality during the pandemic further contributed to disparities, notably at younger ages, where the mortality risk from COVID-19 was small. This is an urgent call to think broadly about the impacts of COVID-19 on health and mortality and to center equity in pandemic response and preparedness planning.