Variation in COVID-19 Disease Severity and Clinical Outcomes Between Different ABO Blood Groups

The primary objective of this study was to explore whether coronavirus disease 2019 (COVID-19) severity and outcomes varied between different ABO blood groups. This retrospective study included 363 COVID-19 confirmed patients who had their blood group recorded in the hospital medical records, from March to June 2020. Data representing demographics, clinical features, vital signs, laboratory findings, and COVID-19 outcomes were collected. Multivariate logistic regression was used for analysis and the results were adjusted for sociodemographic, clinical, and laboratory variables. The patients' mean age was 50 ± 17.8 years. Of the 363 patients, 30% were blood group A, 22.3% were blood group B, 8.8% were blood group AB, and 38.8% were blood group O. Bivariate analysis showed that patients with blood group AB were more likely to be free of any medical disease (65.6%) compared to other blood groups (p = 0.007). Fever was the most common presenting complaint (66.7%), and it did not significantly vary with changes in ABO blood groups (p = 0.230). Regarding laboratory characteristics, only C-reactive protein (CRP) levels were significantly associated with the blood groups, with high levels seen in blood groups A, B, and O (p = 0.036). In multivariate analysis, variations in emergency department (ED) disposition, requirement of intensive care unit care, and requirement of mechanical ventilation were not statistically significant among the different ABO blood groups. Furthermore, no correlation was found between hospital death and the different ABO blood groups. In conclusion, COVID-19 is most prevalent among patients with blood group O and least prevalent among those with blood group AB. No particular blood group had worse COVID-19 disease severity and outcomes than other blood groups. Therefore, we believe that ABO blood grouping should not be used as a major assessment tool for COVID-19 disease severity and outcome, and other known risk factors should be investigated.