Association between ABO Blood Group and COVID-19 Pneumonia Severity: A Cross-Sectional Study from Ethiopia's First Designated COVID-19 Treatment Center

ABSTRACT Background: Coronavirus disease 2019 (COVID19), caused by severe acute respiratory syndrome coronavirus 2, spreads rapidly and can cause severe acute respiratory failure; advanced age, chronic disease, and other comorbidities increase the risk of severe infection. By early 2022, more than 477 million cases and 6.11 million deaths had been reported globally. This study assessed the association between ABO blood group and severity of COVID-19 pneumonia among patients admitted to Eka Kotebe General Hospital, Addis Ababa, Ethiopia. Methods: A hospital-based cross-sectional study was conducted using systematic random sampling; data were abstracted from patient records, and severity was modeled using ordinal logistic regression, with multicollinearity and the proportional odds assumption checked via the variance inflation factor and test of parallel lines, and model fit assessed by likelihood ratio chi-square and goodness of fit tests. Results: Of 355 patients included (100% response rate), 54.9% were male and 31.0% were older than 61 years (median age, 48 years; interquartile range, 33-65). Overall, 10.14% were asymptomatic, 24.79% had mild/moderate disease, 60.56% had severe disease, and 4.51% had critical disease. Pregnancy and presence of complications were significantly associated with severity (adjusted odds ratio, 0.15 [95% CI, 0.04-0.57] and 14.96 [95% CI, 4.14-54.01], respectively); ABO blood group showed no association with severity. Conclusion: These findings demonstrate a substantial association between COVID-19 severity and complications and pregnancy, but not ABO blood group.