Are blood groups related to the distribution and severity of COVID-19? A cross-sectional study in a tertiary care hospital in South India.

Background: Blood groups are inherited traits that affect the susceptibility/severity of a disease. A clear relationship between coronavirus disease 2019 (COVID-19) and ABO blood groups is yet to be established in the Indian population. This study aimed to demonstrate an association of the distribution and severity of COVID-19 with ABO blood groups. Methods: A cross-sectional study was conducted after obtaining ethics approval (IEC 207/20) among hospitalized patients using in-patient records and analyzed on SPSS-25. Chi-square tests were used for the analysis of categorical data and independent sample t-test/Mann-Whitney U tests were used for continuous data. Results: The B blood group had the highest prevalence among COVID-19-positive patients. The AB blood group was significantly associated with acute respiratory distress syndrome (ARDS) (p = 0.03), sepsis (p = 0.02), and septic shock (p = 0.02). The O blood group was associated with significantly lower rates of lymphopenia and leucocytosis. However, no significant clinical association was seen in the O blood group. Conclusion: This study has demonstrated that blood groups have a similar distribution among patients hospitalized with COVID-19 in the South Indian population. Additionally, it preludes to a possible association between the AB blood group and ARDS, sepsis, and septic shock. Further studies having a larger representation of AB blood groups, especially in patients hospitalized for critical COVID-19, with adjustment for possible covariates, are warranted to provide a reliable estimate of the risk in the South Indian population.