Associations Between Blood Group and COVID-19 Mortality, Severity, and Length of Hospitalization

Objectives: This study aimed to investigate the relationship between ABO blood groups and the mortality rate, disease severity, and length of hospitalization (LOH) in patients with COVID-19. Methods: A hospital-based cross-sectional study was conducted from March 1 to June 1, 2020. Demographics, comorbidities, and biochemical data were gathered, and the association of ABO blood groups with mortality rate, disease severity (hospitalization in general ward or ICU), and LOH was investigated using standard univariate analysis and logistic regression. Results: Out of 398 patients who were positive for COVID-19, 65 (16.3%), 71 (17.8%), 9 (2.3%), and 252 (63.3%) had blood groups of A, B, AB, and O, respectively. Multivariate analysis showed that for each day of hospitalization, the odds of death increased by 4% (OR = 1.04, P = 0.004). Also, the chance of death was 43% lower in patients with blood group O than those with other blood groups (OR = 0.574, P = 0.032). In patients with blood group A, the chance of hospitalization at the ICU was five times higher compared to patients with other blood groups (OR = 5.038, P = 0.002). The LOH was 5.437 and 2.6 days shorter in Rh-positive patients and those with blood group B, while patients with blood group A were hospitalized 3.7 days longer than individuals with other blood groups. Conclusions: The present study showed that COVID-19 mortality was lower in patients with blood group O compared to individuals with other blood groups. Also, blood group A was associated with more severe COVID-19 disease and longer LOH.