A history of COVID-19 can double the risk of heart attack, stroke or death according to new research led by Cleveland Clinic and the University of Southern California.

The study found that people with any type of COVID-19 infection were twice as likely to have a major cardiac event, such as heart attack, stroke or even death, for up to three years after diagnosis. The risk was significantly higher for patients hospitalized for COVID-19 and more of a determinant than a previous history of heart disease.

Further genetic analysis also revealed individuals with a blood type other than an O (such as A, B or AB) were twice as likely to experience an adverse cardiovascular event after COVID-19 than those with an O-blood type.

Published in Arteriosclerosis, Thrombosis and Vascular Biology, the researchers used UK Biobank data from 10,005 people who had COVID-19 and 217,730 people who did not get infected between February to December 2020.

"Worldwide over a billion people have already experienced COVID-19. The findings reported are not a small effect in a small subgroup," said co-senior study author Stanley Hazen, M.D., Ph.D., chair of Cardiovascular and Metabolic Sciences in Cleveland Clinic's Lerner Research Institute and co-section head of Preventive Cardiology. "The results included nearly a quarter million people and point to a finding of global health care importance that promises to translate into a rise in cardiovascular disease globally."

Certain genetic variants are already linked to coronary artery disease, heart attack and COVID-19 infection. The researchers completed a genetic analysis to see if any of these known genetic variants contribute to elevated coronary artery disease risk after COVID-19.

None of the known genetic variants were drivers of the enhanced cardiovascular events observed post COVID-19. Instead, the data highlighted an association between elevated risk and blood type.

Previous research has shown that people who have A, B or AB blood types were also more susceptible to contracting COVID-19.

"These findings reveal while it's an upper respiratory tract infection, COVID-19 has a variety of health implications and underscores that we should consider history of prior COVID-19 infection when formulating cardiovascular disease preventive plans and goals," said Dr. Hazen.

"The association uncovered by our research indicates a potential interaction between the virus and the piece of our genetic code that determines blood type and signals the need for further investigation," said Dr. Hazen. "A better understanding of what COVID-19 does at the molecular level may potentially teach us about pathways linked to cardiovascular disease risk."

Hooman Allayee, Ph.D., of USC's Keck School of Medicine, was co-senior author of the paper.

"Our data suggesting that risk of heart attacks and strokes was especially higher among COVID-19 patients with A, B, or AB blood types has significant clinical implications," Dr. Allayee said.

"Given our collective observations and that 60% of the world's population have these non-O blood types, our study raises important questions about whether more aggressive cardiovascular risk reduction efforts should be considered, possibly by taking into consideration an individual's genetic makeup."

The findings show that the long-term risk associated with COVID-19 "continues to pose a significant public health burden" and that further investigation is needed, according to the authors.