Association of Race and Ethnicity with COVID-19 Test Positivity and Hospitalization Is Mediated by Socioeconomic Factors

Abstract

Rationale: Black race and Hispanic ethnicity are associated with increased risks for coronavirus disease (COVID-19) infection and severity. It is purported that socioeconomic factors may drive this association, but data supporting this assertion are sparse. Objectives: To evaluate whether socioeconomic factors mediate the association of race/ethnicity with COVID-19 incidence and outcomes. Methods: We conducted a retrospective cohort study of adults tested for (cohort 1) or hospitalized with (cohort 2) COVID-19 between March 1, 2020, and July 23, 2020, at the University of Miami Hospital and Clinics. Our primary exposure was race/ethnicity. We considered socioeconomic factors as potential mediators of our exposure's association with outcomes. We used standard statistics to describe our cohorts and multivariable regression modeling to identify associations of race/ethnicity with our primary outcomes, one for each cohort, of test positivity (cohort 1) and hospital mortality (cohort 2). We performed a mediation analysis to see whether household income, population density, and household size mediated the association of race/ethnicity with outcomes. Results: Our cohorts included 15,473 patients tested (29.0% non-Hispanic White, 48.1% Hispanic White, 15.0% non-Hispanic Black, 1.7% Hispanic Black, and 1.6% other) and 295 patients hospitalized (9.2% non-Hispanic White, 56.9% Hispanic White, 21.4% non-Hispanic Black, 2.4% Hispanic Black, and 10.2% other). Among those tested, 1,256 patients (8.1%) tested positive, and, of the hospitalized patients, 47 (15.9%) died. After adjustment for demographics, race/ethnicity was associated with test positivity-odds-ratio (95% confidence interval [CI]) versus non-Hispanic White for Non-Hispanic Black: 3.21 (2.60-3.96), Hispanic White: 2.72 (2.28-3.26), and Hispanic Black: 3.55 (2.33-5.28). Population density mediated this association (percentage mediated, 17%; 95% CI, 11-31%), as did median income (27%; 95% CI, 18-52%) and household size (20%; 95% CI, 12-45%). There was no association between race/ethnicity and mortality, although this analysis was underpowered. Conclusions: Black race and Hispanic ethnicity are associated with an increased odds of COVID-19 positivity. This association is substantially mediated by socioeconomic factors.

Keywords: coronavirus; ethnic groups; incidence; race factors; socioeconomic factors.

Figure 1.

Adjusted association of race/ethnicity with test positivity in the absence and presence of socioeconomic factors. The model is also adjusted for demographic factors (age, sex, and payor). CI = confidence interval.

Figure 2.

Association of race and ethnicity with socioeconomic factors. (A) Population density. (B) Median household income. (C) Average household size. Data are given as medians with interquartile ranges (white boxes); in models inclusive of demographics (age, sex, and payor), race/ethnicity was associated with each of population density (P < 0.001), median household income (P < 0.001), and average household size (P < 0.001).

Figure 3.

Mediation of the association of race and ethnicity with test positivity by socioeconomic factors. (A) Model without potential mediation factors. (B) Model with potential mediation factors. All socioeconomic factors were included in one model as a group; mediation analysis evaluating the impact of each factor separately determined that population density mediated 17% (95% confidence interval [CI], 11–31%), median income mediated 27% (95% CI, 18–52%), and household size mediated 20% (95% CI, 12–45%) of the association of race/ethnicity with test positivity.

Figure 4.

Adjusted association of race/ethnicity with mortality in the absence and presence of socioeconomic factors. The model is also adjusted for demographic factors (age, sex, and payor), comorbidities, and Sequential Organ Failure Assessment score. CI = confidence interval.