Association of Blood Type on Clinical Outcomes in Black/African Americans Hospitalized for COVID-19 Infection

Introduction: Early studies from Wuhan, China have reported an association between blood type and outcomes in COVID-19 infected patients. Conflicting reports in literature have investigated the protective role of blood type O against worst outcomes associated with COVID-19 infections. Approximately 50% of Black/African Americans (AA) have blood group O. Our study is the only study to date looking at the association between Black/AA and blood type. We aimed to determine the association between blood type and Black/AA patients hospitalized for COVID-19.

Methods: We retrospectively reviewed data on patients with known blood type, who were admitted for COVID-19 at a single center between March and April 2020. We excluded other races in our study because only about 2% of the population was Caucasian and 8% representing other races, representing a small subset of patients under study whereas Black/AA represented about 90% of our hospitalized patients. Patients were stratified into 4 groups based on their ABO blood type. Baseline demographic, clinical characteristics and clinical course of the disease were compared. The primary end point was in-hospital mortality. Secondary endpoints included admission to the intensive care unit (ICU), acute kidney injury requiring hemodialysis and length of stay (LOS).

Results: During the study period, a total of 256 patients were reviewed. Distribution of ABO type was as follows; A: (N=65) 25%, B: (N=62) 24%, AB: (N=9) 4%, O: (N=120) 47%. Compared to blood types A, B and O, AB patients were younger (mean; yrs. 63 vs. 63 vs. 62 vs. 43 yrs. p=0.0242). Blood type B patients were more likely to present with nausea, than groups A, AB, and O. (27% vs. 10% vs. 0% vs. 5%; p=0.017). All other characteristics including baseline inflammatory markers were comparable. There was no difference among groups regarding in-hospital mortality (A: 39% B: 29% AB: 33% O: 31% p value: 0.676) or admission to the ICU (A:31% B: 28% AB: 33% O: 34% p value: 0.840). The incidence of acute kidney injury requiring hemodialysis was higher in blood type A patients compared to B, AB, and O. (31% vs. 0% vs. 23% vs. 19%; p=0.046). In hospital LOS was comparable among all groups.

Conclusions: In this single center analysis of black/AA patients admitted for COVID-19, there was no association between blood type and in-hospital mortality or admission to ICU. Blood type A patients had a higher propensity of kidney injury, but this did not translate into worse in-hospital survival.