How COVID-19 Cardiovascular Risks Relate to Blood Type

Researchers examining the long-term cardiovascular risks of COVID-19 have highlighted a significant genetic association with ABO blood types.

The study, published in Arteriosclerosis, Thrombosis, and Vascular Biology, used data from the UK Biobank to assess major adverse cardiac events (MACE) in 10,005 COVID-19 patients compared to 217,730 population controls, with up to 1,000 days of follow-up. The American study team aimed to determine whether COVID-19 increased the risk of MACE – including myocardial infarction (MI), stroke, and all-cause mortality – and whether this risk varied by blood type.

Hospitalization for COVID-19 significantly increased the risk of MACE (hazard ratio [HR], 3.85; 95 percent CI, 3.51–4.24), and this heightened risk persisted for nearly three years post-infection. Corresponding author, Hooman Allayee, adds, “"An important finding was that the increased risk of adverse cardiac events seen in severe COVID patients was comparable to the risk observed in patients who already have heart disease or other cardiovascular risk factors, such as diabetes.”

Most notably, the study revealed a strong genetic interaction between COVID-19 hospitalization and individuals with non-O blood types (A, B, or AB), who experienced a significantly increased risk of thrombotic events, such as MI or stroke, compared with those with blood type O. Specifically, the hazard ratio for thrombotic events in non-O blood type patients was 1.65 (95 percent CI, 1.29–2.09; P = 4.8×10⁻⁵), while no increased risk was observed in patients with blood type O (HR, 0.96; 95 percent CI, 0.66–1.39; P = 0.82).

Allayee comments, “It appears that genetics plays a role in the risk of heart attacks and stroke, since individuals with blood type A, B, or AB had higher risk than patients with blood type O. This of course raises the question of why – but a biological mechanism for the increased risk of heart attacks and strokes in non-O individuals requires further study.”

The research underscores the importance of considering ABO blood type in assessing long-term cardiovascular risk in patients hospitalized with COVID-19.