The following article features coverage from the American Society of Hematology 2020 meeting. Click here to read more of Hematology Advisor‘s conference coverage.

ABO blood groups and Rhesus (Rh) factor were not correlated with coronavirus disease 2019 (COVID-19) ICU admission, use of mechanical ventilation, or mortality in hospitalized COVID-19 patients, according to study results presented at the virtual 62nd American Society of Hematology (ASH) Annual Meeting and Exposition. Findings were presented by Aula Ramo, MD, of the Henry Ford Hospital in Detroit, Michigan.

“As the pandemic started, multiple studies were coming out with different findings in regards to associations between ABO blood groups and COVID-19 in terms of disease susceptibility as well as disease severity,” said Dr Ramo.

Dr Ramo and colleagues conducted a retrospective study to evaluate the association between ABO blood groups with ICU admission as a proxy for disease severity and mortality/survival (updated July 15, 2020) in patients hospitalized with COVID-19. The investigators reviewed records of patients with confirmed COVID-19 hospitalized within the Henry Ford Health System between March 10 and April 30, 2020. Additional variables assessed were age, gender, race, comorbidities, and intubation.  

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Overall, 1488 patients hospitalized with COVID-19 and with ABO blood group data were identified (median age, 68 years; range, 19-99 years). The slight majority of patients were women (54%) and Black/African American (58%).

Patients’ blood groups were 32.6% group A, 18.5% group B, 44.2% group O, and 4.6% group AB. ICU admission was required for 31.5% patients, and of those patients, 78.8% (370/469) were intubated. As of July 15, 2020, 27.6% of all patients had died.

No associations were identified between ABO blood groups or Rh factor (D antigen) and ICU admission, intubation, or mortality. In a univariate analysis, patient characteristics and comorbidities associated with increased mortality included male sex (OR, 1.75; 95% CI, 1.39-2.20; P <.001), Caucasian/White race (OR, 1.79; 95% CI, 1.42-2.25; P <.001), age 65 years or older (OR, 5.0; 95% CI, 3.78-6.63; P <.001), coronary artery disease (OR, 1.83; 95% CI, 1.41-2.38; P <.001), chronic obstructive pulmonary disease ([COPD]; OR, 1.82; 95% CI, 1.36-2.44; P <.001), and malignancy (OR, 1.75; 95% CI, 1.32-2.33; P <.001).  

Multivariate analysis of predictors of mortality confirmed the findings of the univariate analysis for age 65 years or older (OR, 4.27; 95% CI, 3.19-5.71; P <.001), male sex (OR, 1.57; 95% CI: 1.23-2.01; P <.001), Caucasian/White race (OR, 1.46; 95% CI, 1.14-1.86; P=.003), and COPD (OR, 1.49; 95% CI, 1.09-2.04; P =.013).

Limitations of the study included the retrospective design and nonstandardized protocols for care of patients with COVID-19 at the time of the study.

“Our study did not find ABO blood groups nor Rh factor correlated with disease severity, the use of mechanical ventilation, or mortality in hospitalized COVID-19 patients,” concluded Dr Ramo. “Interestingly, contradictory to other studies that were coming out at the time, African American patients were not at increased risk of dying from COVID-19 compared to Caucasians.”

Read more of Hematology Advisor’s coverage of the ASH 2020 meeting by visiting the conference page.


Ramo A, Mehrotra H, Onwubiko I, et al. Correlation between ABO blood groups and disease severity and mortality in hospitalized COVID-19 patients. Presented at: 62nd American Society of Hematology (ASH) Annual Meeting and Exposition; December 5-8, 2020. Abstract 104.