Patient and Hospital Factors Associated With Differences in Mortality Rates Among Black and White US Medicare Beneficiaries Hospitalized With COVID-19 Infection

Abstract

Importance: Black patients hospitalized with COVID-19 may have worse outcomes than White patients because of excess individual risk or because Black patients are disproportionately cared for in hospitals with worse outcomes for all.

Objectives: To examine differences in COVID-19 hospital mortality rates between Black and White patients and to assess whether the mortality rates reflect differences in patient characteristics by race or by the hospitals to which Black and White patients are admitted.

Design, setting, and participants: This cohort study assessed Medicare beneficiaries admitted with a diagnosis of COVID-19 to 1188 US hospitals from January 1, 2020, through September 21, 2020.

Exposure: Hospital admission for a diagnosis of COVID-19.

Main outcomes and measures: The primary composite outcome was inpatient death or discharge to hospice within 30 days of admission. We estimated the association of patient-level characteristics (including age, sex, zip code-level income, comorbidities, admission from a nursing facility, and days since January 1, 2020) with differences in mortality or discharge to hospice among Black and White patients. To examine the association with the hospital itself, we adjusted for the specific hospitals to which patients were admitted. We used simulation modeling to estimate the mortality among Black patients had they instead been admitted to the hospitals where White patients were admitted.

Results: Of the 44 217 Medicare beneficiaries included in the study, 24 281 (55%) were women; mean (SD) age was 76.3 (10.5) years; 33 459 participants (76%) were White, and 10 758 (24%) were Black. Overall, 2634 (8%) White patients and 1100 (10%) Black patients died as inpatients, and 1670 (5%) White patients and 350 (3%) Black patients were discharged to hospice within 30 days of hospitalization, for a total mortality-equivalent rate of 12.86% for White patients and 13.48% for Black patients. Black patients had similar odds of dying or being discharged to hospice (odds ratio [OR], 1.06; 95% CI, 0.99-1.12) in an unadjusted comparison with White patients. After adjustment for clinical and sociodemographic patient characteristics, Black patients were more likely to die or be discharged to hospice (OR, 1.11; 95% CI, 1.03-1.19). This difference became indistinguishable when adjustment was made for the hospitals where care was delivered (odds ratio, 1.02; 95% CI, 0.94-1.10). In simulations, if Black patients in this sample were instead admitted to the same hospitals as White patients in the same distribution, their rate of mortality or discharge to hospice would decline from the observed rate of 13.48% to the simulated rate of 12.23% (95% CI for difference, 1.20%-1.30%).

Conclusions and relevance: This cohort study found that Black patients hospitalized with COVID-19 had higher rates of hospital mortality or discharge to hospice than White patients after adjustment for the personal characteristics of those patients. However, those differences were explained by differences in the hospitals to which Black and White patients were admitted.

Figure 1.. Geographic Distribution and Number of Black and White Patients Hospitalized With COVID-19 in the Sample

Figure 2.. Distribution of Black and White Patients Across 1118 Hospitals

The 1118 hospitals are divided into quintiles by the relative proportion of Black and White patients from the sample admitted to them; that is, the x-axis represents the differences in proportion of Black patients in our sample within a hospital. Each column shows the split of Black and White patients in the sample who were admitted to hospitals in that quintile. Note that quintiles are found on the hospital level and as such may contain different numbers of patients. Quintile 1 (hospital patient population comprises >50.0% Black patients) includes 5455 patients; quintile 2 (patient population comprises 30.0%-50.0% Black patients), 7483 patients; quintile 3 (patient population comprises 19.0%-30.0% Black patients), 8287 patients; quintile 4 (patient population comprises 9.2%-19.0% Black patients), 9887 patients; and quintile 5 (patient population comprises <9.2% Black patients), 13 105 patients.

Figure 3.. Simulated Improvement in Population Mortality for 10 758 Black Patients Had They Been Admitted to the Same Hospitals as White Patients

The distribution reflects a simulation of 1000 replications of the estimated mean event rate had the Black patients been distributed as the White patients were. A, The solid vertical line corresponds to an observed rate of mortality or discharge to hospice of 13.48% for Black patients. The dashed blue line corresponds to an estimated rate of mortality or discharge to hospice of 12.23%. B, Difference between observed and estimated event rates for each of 1000 simulations. The orange diamond corresponds to the mean value of 1.25%. The horizontal line in the middle of the box indicates the median, and the box indicates the first and third quartiles.