Title

Association between ABO blood type/Rh antigen status and clinical outcomes in hospitalized patients with Coronavirus Disease 2019 (COVID-19): a retrospective cohort study in a large US hospital system

Authors

Elizabeth Benge, MD, Sameera Baig, MD, Gundip Dhillon, DO, Hatim Gemil, MD, Hossein Akhondi, MD

Introduction

Since the onset of the COVID-19 pandemic, clinicians have sought to identify patient groups most vulnerable to the virus. This ignited a worldwide investigation into the risk factors that precipitate COVID-19 related disease. One patient-level characteristic under investigation is ABO blood group/Rh-antigen status. Thus far, the evidence on the association between ABO blood group/Rh-antigen status and COVID-19 outcomes has been conflicting. Some studies found an existing association between ABO group and COVID-19 infection. For instance, one study found that patients with blood group A were at increased odds of testing positive for COVID-19 as compared to the general population. Participants with O positive blood group were the least likely to test positive (1). A subsequent study also found O positive blood to engender a seemingly protective effect against COVID-19 (2). Conversely, other studies have found no association between COVID-19 positivity and ABO blood group (3). Given the ongoing uncertainty surrounding the association between blood group and COVID-19 related disease, we conducted a retrospective cohort study to evaluate the association between ABO blood group and outcomes for hospitalized patients who tested positive for COVID-19 in regards to length of stay, in-hospital mortality, complications and hospital re-admission rates.

Methods

We conducted a retrospective cohort study of adult patients over the age of eighteen admitted to the hospital from the ED after testing positive for COVID-19 (March 2020-December 2020). Patients without a type and screen were excluded. Collected data included patients' demographics, clinical characteristics, laboratory test results, ICU admission status, length of hospitalization, and re-admission status. In our statistical analyses, the ABO blood group types compared were: A Negative, A Positive, AB Negative, AB Positive, B Negative, B Positive, O Negative, and O Positive.

Results

40,816 patients (median age: 37.5 years) were included in this study. There is no significant difference (P-Value = 0.1930) between the percentage of patients in each blood type group that experienced in-hospital mortality (P-Value = 0.1930) or ICU admission (P-Value = 0.4929). There is no significant difference for hospital readmission rates at 30 days (P-Value = 0.4287), 60 days (P-Value = 0.4509), or 90 days (P-Value = 0.3516). In terms of viral sequelae, there is no significant difference between the percentage of patients in each blood type group that experienced in-hospital: stroke (P-Value = 0.1954), DVT (P-Value = 0.4807), PE (P-Value = 0.4343), atrial fibrillation (P-Value = 0.9475), ventricular tachycardia (P-Value = 0.5439), ventricular fibrillation (P-Value = 0.2399), myocardial infarction (P-Value = 0.4245), gastroenteritis (P-Value = 0.7074), pancreatitis (P-Value = 0.8648), acute respiratory failure (P-Value = 0.1408), or acute on chronic respiratory failure (P-Value = 0.4138). There is not a significant difference (P-Value = 0.7739) in the mean length of stay between blood type groups.

Conclusion

Blood group type/Rh-antigen status is not associated with clinically relevant COVID-19 outcomes such as length of hospitalization, ICU admission, and a wide range of viral sequelae. Future research should focus on elucidating different hematologic risk factors that may predispose patients to more severe COVID-19 related disease, such as the presence of anti-PF4/heparin antibodies.

References

1. Zhao J, Yang Y, Huang H, Li D, Gu DL. X.,… Wang, PG (2020). Relationship between the ABO blood group and the COVID-19 susceptibility. MedRxiv. 2. Zietz M, Zucker J, Tatonetti NP. Testing the association between blood type and COVID-19 infection, intubation, and death. MedRxiv. 2020 Jan 1. 3. Latz CA, DeCarlo C, Boitano L, Png CM, Patell R, Conrad MF, Eagleton M, Dua A. Blood type and outcomes in patients with COVID-19. Annals of hematology. 2020 Sep;99(9):2113-8.