ABO and Rh blood groups, demographics, and comorbidities in COVID-19 related deaths: a retrospective study in Split-Dalmatia County, Croatia

Brdar, I.; Jerkovic, I.; Basic, Z.; Kunac, N.; Anđelinovic, D.; Bezic, J.; Kruzic, I.; Vuko, A.; Anđelinovic, S.

Aim: To examine ABO and Rh blood group distribution in COVID-19 related deaths considering demographics and pathological conditions. Materials and Methods: We conducted a retrospective study at the University Hospital Centre Split, Croatia, that included 245 COVID-positive individuals that died from April 8, 2020, to January 25, 2021. From the hospital database, we extracted data on their blood groups, demographics, and pre-existing comorbidities. To compare findings with the general population, we used information from collected blood group donations (n = 101357) and statistical reports of non-COVID deaths from 2019 (n = 4968). Results: The proportion of males was significantly higher in analyzed subjects than in non-COVID deaths from 2019 (63.7% vs. 48.9%, P < 0.001), while the proportion of older individuals did not differ (P = 0.8). The most common pre-existing diseases were hypertension (59.6%), diabetes (37.1%), heart failure (28.8%), digestive disorder (26.5%), and solid tumor (21.6%). The ABO distribution in the deceased and donors' group showed statistically significant differences, with the higher prevalence of A/AB group and lower prevalence of 0, but with individual differences significant only for AB and non-AB groups. There was a significantly reduced proportion of females within the deceased with group 0 (P = 0.014) and a higher proportion of AB individuals with coronary heart disease (P = 0.024), while other differences were not significant. Conclusion: The study confirmed a higher risk of death in male individuals. The lower proportion of type 0 in deceased individuals was more pronounced in females, implying that group 0 is not necessarily an independent protective factor. Among analyzed comorbidities, coronary heart disease was identified as a potential risk factor for AB individuals.