The Association Between Black vs. White Race and 30-Day Hospitalization Among People Diagnosed with COVID-19 Within an Integrated Care Setting: a Cohort Study

Background Black Americans are more likely to experience hospitalization from COVID-19 compared with White Americans. Whether this excess risk differs by age, sex, obesity, or diabetes, key risk factors for COVID hospitalization, among an integrated population with uniform healthcare access, are less clear. Methods We identified all adult members (≥ 18 years) of Kaiser Permanente Georgia (KPGA) diagnosed with COVID-19 between January 1, 2020, and September 30, 2021 ( N = 24,564). We restricted the analysis to members of Black or White race identified from electronic medical records. Our primary outcome was first hospitalization within 30 days of COVID-19 diagnosis. To assess the association between race and 30-day hospitalization, we performed multivariable logistic regression adjusting for several member and neighborhood-level characteristics, and tested for interactions of race with age, sex, diabetes, and obesity. A regression-based decomposition method was then used to estimate how much of the observed race disparity in 30-day hospitalization could be explained by member and neighborhood-level factors. Results Overall, 11.27% of Black KPGA members were hospitalized within 30 days of a COVID diagnosis, as compared with 9.44% of White KPGA members. Black (vs. White) KPGA members had a 34% (aOR: 1.32 [95% CI: 1.19–1.47]) higher odds of 30-day hospitalization following COVID-19 after accounting for clinical differences. The odds of 30-day hospitalization in Black vs. White KPGA members did not differ significantly by sex (men: 1.46 [1.25–1.70]; women: 1.24 [1.07–1.43]), by age (18–29 years: 1.33 [0. 841–2.10]; 30–49 years: 1.26 [1.02–1.56]; ≥ 50 years: 1.24 [1.10–1.41]); by diabetes status (with diabetes: 1.38 [1.16–1.66]; without diabetes: 1.26 [1.11–1.44]), or by obesity (with obesity: 1.31 [1.15–1.50]; without obesity: 1.28 [1.06–1.53]). Factors that, if Black and White KPGA members had the same level of exposure, would be most likely to reduce the Black-White disparity in 30-day hospitalization from COVID-19 were obesity, history of flu vaccine, and neighborhood-level income and social vulnerability. Conclusions Early in the pandemic, Black (vs. White) members of an integrated health system had higher odds of being hospitalized within 30 days of COVID-19 diagnosis and this excess risk was similar by sex, age, and comorbidities. Factors that explained the largest proportions of race-based disparities were obesity, receipt of flu vaccine, and neighborhood-level social determinants of health. These findings suggest that social determinants of health, or other unmeasured factors, may be drivers of racial disparities in COVID-19 outcomes.