ABO Blood Group Type Association With COVID-19 Severity
Condition: COVID-19; Blood Group Antigen Abnormality; Blood Group Incompatibilities; Diabetes Mellitus; COVID-19 Pandemic
MeSH terms: COVID-19
Study type: Observational

Summary: 
      The COVID-19 pandemic has caused a significant healthcare burden and remains a heavily
      researched disease entity. Originating in Wuhan, China in late 2019, SARS-CoV-2 has infected
      over 600 million individuals worldwide. ABO blood groups have been known to increase the
      human body's susceptibility to different pathogens, such as hepatitis B virus, MERS-COV,
      SARS-COV, norovirus, and malaria, to name a few. As such, the association of ABO blood groups
      and COVID-19 infection and disease severity has come into question.
    

Detailed description: 
      The COVID-19 pandemic has caused a significant healthcare burden and remains a heavily
      researched disease entity. Originating in Wuhan, China in late 2019, SARS-CoV-2 has infected
      over 600 million individuals worldwide. ABO blood groups have been known to increase the
      human body's susceptibility to different pathogens, such as hepatitis B virus, MERS-COV,
      SARS-COV, norovirus, and malaria, to name a few. As such, the association of ABO blood groups
      and COVID-19 infection and disease severity has come into question.

      Early reports have indicated a significant relationship of ABO blood group types to the risk
      of infection with SARS-CoV-2. Specifically, the first systematic review and meta-analysis by
      Wu et al. in October 2020 cited that blood type A had increased risk for infection with
      SARS-CoV-2 and blood type O had decreased risk of infection. Another early meta-analysis by
      Zaidi et al. cited that blood type A had increased odds of infection, type O had decreased
      odds of infection, type AB had increased risk of disease severity, and type B had decreased
      risk of demise.

      As more multi-national data became available, as a result of global concerted efforts, larger
      studies produced data to further investigate this connection. Overall, the majority of
      studies reproduced similar data: type O had decreased risk of infection with SARS-CoV-2,
      while type A had increased risk of infection. One study in the United Kingdom failed to
      produce a relationship between blood types and COVID-19. As more data became available,
      several studies were able to study the association of blood group type with mortality and
      disease severity; however, the data regarding this is inconsistent. Gutierrez-Valencia et al.
      did not find an association with blood types and ICU admission or mechanical ventilation;
      however, they did note an increased risk of mortality in blood type A. Liu et al. and Pereira
      et al. demonstrated that there is also increased risk of mortality in blood type A. Jerico et
      al. noted a lower risk for ICU admission in blood type O. Goel et al. noted an increased risk
      of disease severity in blood type A. As evident, it seems that blood type A has increased
      risk of mortality and, likely, disease severity.

      In this study, we aim to evaluate association of blood types with mortality and disease
      severity at a county hospital in Southern California. We will review charts for patients
      infected with SARS-CoV-2 during a two-year time period, evaluating mortality, oxygen
      requirements, and patient historical factors. Through this study, we aim to gain a better
      understanding of how blood group types may affect patient outcomes in the setting of
      COVID-19.
    

Intervention name(s): No Intervention
Intervention type(s): Other
Intervention description(s): Difference in outcomes in patients with COVID-19 diagnosis and ABO blood groups
Observational model: Cohort
Time perspective: Retrospective
Sampling method: Non-Probability Sample
Study population: 
        To evaluate blood types and their associations with COVID-19 disease severity in patients
        older than 18 years of age.