Epidemiologic Risk Modeling of Disproportionate Burden of SARS-CoV-2 Case Positivity and COVID-19 Mortality among Blacks/African Americans in Washington DC, USA

Abstract

Background: Historically, populations with deprived optimal care, preventive health services, value-based care, and low socio-economic status with marginalized social hierarchy had been observed with poor health outcomes and excess mortality during pandemics. The current COVID-19 global pandemic mirrors the flu pandemic of 1918, where the social gradient predicted the disproportionate burden of mortality among blacks in the United States (US). The current study aimed to assess the racial differentials in SARS-Cov-2 case positivity, case fatality and mortality in Washington DC, US as well as the potential explanatory model therein.

Materials and Methods: A cross-sectional ecologic design was used to examine the COVID-19 data from the Washington DC Department of Health (https://coronavirus.dc.gov/data ) by race/ethnicity, sex, ward (geographic locale), and age. This predictive model examined the pre- (November, 2020) and post-thanksgiving (December, 2020) data for trends. While the variables examined were in aggregate data format, chi square statistic and binomial regression models were used for variable characterization by race and mortality risk race prediction respectively.

Results: During late November, the SARS-Cov-2 case positivity in Washington DC was higher among Blacks/AA (n=9,441(46.7%)) relative to Whites, 4603 (22.8%). With respect to Hispanics, the SARS-Cov-2 case positivity was 4,853 (24.1%) and 13,477 (66.9%) among non-Hispanics. With respect to COVID-19 mortality, this was lowest among non-Hispanic Whites (NHW), 1.50%, intermediate among Hispanics (1.81%), and highest among non-Hispanic Blacks (NHB), 5.30%. There was sex differential in mortality cumulative incidence (CmI), with males (57.0%) compared to females (43.0%) illustrating higher mortality. The mortality CmI by age was lowest among cases, 20-29 years (6.4%), intermediate among cases, 50-69 years (36.3%) and highest among individuals, 70 years and older, 58.7%. With respect to the geographic locale (DC-Ward), the mortality CmI was higher in DC- Wards 4-6 (39.3%) and wards DC-7-8 (35.4%) but lower in DC-Wards 1-3 (22.1%). The mortality risk from COVID-19 illustrated racial/ethnic differentials. Relative to NHW in Washington DC, NHB were almost 4 times as likely to die from COVID-19 in November 2020 prior to Thanksgiving, prevalence odds ratio, (pOR)=3.62, 95%CI, 2.78-4.73, Attributable fraction of exposed (AFE),72%, while Hispanics were 25% more likely to die, Hispanics, pOR=1.25, 95%CI, 1.0-1.74, AFE(18%).

During the first week in December, post –thanksgiving period, the SARS-Cov-2 case positivity was lower among Whites (n, 5719, (23.0%)) compared to Blacks/AA, 11,218 (47%). The CmI mortality was highest among NHB, n=521 (74%), intermediate among Hispanics, n=93 (13.2%) and lowest among NHW, n=72, (10.2%). Similarly, there was racial differential in mortality risk,with increased risk observed among Blacks/AA, relative to their White counterparts in DC. Compared to Whites, Blacks/AA were 4 times as likely to die from COVID-19, pOR=4.00, 95%CI, 2.87-4.80, AFE (73%).

Conclusions: There were racial/ethnic disparities in SARS-Cov-2 case positivity, COVID-19 mortality and mortality risk, which was higher among Blacks/AA relative to their White counterparts in Washington DC. Additionally, mortality was higher in male compared to female as well as DC-ward variation by mortality.