ABO Blood Group in Relation to COVID-19 Susceptibility and Clinical Outcomes: A Retrospective Observational Study in the United Arab Emirates.

(1) Background: The association between ABO blood groups and COVID-19 outcomes was investigated in several studies. The results were controversial. This study aimed to explore the association between ABO blood groups and COVID-19 outcomes. (2) Methods: This retrospective study included 303 COVID-19 patients treated at the NMC Royal Hospital in the United Arab Emirates between 8 April 2020 and 30 June 2020. (3) Results: The mean age of patients included in the study was 39.3 ± 10.7 years, and 72.9% of patients were males. The prevalence of blood groups O, A, B, and AB was 40.3%, 27.7%, 25.1%, and 6.9%, respectively. The correlation between ABO blood groups and COVID-19 outcomes was insignificant except in the AB group, with significantly higher odds of disease severity. Increased age, higher body mass index (BMI), and being of male gender increased the risk for pneumonia among all blood groups. Both increased age and higher BMI increased the risk of mortality, and increased age increased the risk of disease severity. Troponin and platelet counts were significantly different in the A group compared to the non-A groups. Time to viral clearance was not different among blood groups. However, adjustment for Rh groups resulted in a significantly shorter time in the B group. (4) Conclusions: There was no significant association between ABO blood groups and COVID-19 outcomes, with the exception of group AB.