Even a mild case of COVID-19 can increase a person's risk of having a serious cardiovascular event — like stroke or heart failure — within a year after infection.
That's according to an open-access study involving more than 11 million people published earlier this month in Nature Medicine. The study, conducted by researchers at the Veterans Health Administration (VA) St. Louis Health Care System and Washington University in St. Louis, pulled data from patients at 1,255 health care facilities across the U.S. The authors zeroed in on 153,760 veterans who tested positive for COVID-19 between March 1, 2020 and January 15, 2021 and survived at least 30 days after the infection. Then, they put together a comparison group of 5.6 million veterans from the same timeframe who didn't test positive for COVID-19, and a second control group of more than 5.9 million people who sought VA care in 2017.
"We've known for a while that COVID-19 is the acute phase of the disease, and in the first 30 days of disease, some people can have heart attacks and blood clots and several complications . . . but what we didn't know is really what happens to people with COVID-19 over the longer term," said Dr. Ziyad Al-Aly, the study's lead author and Chief of Research and Development at the VA St. Louis healthcare system. "What happens to them? Six months down the road, eight months down the road, even up to a year down the road?"
What Al-Aly and his colleagues found was even a mild COVID-19 infection increased a person's risk of having cardiovascular problems — including heart rhythm irregularities, potentially deadly clots in the legs and lungs, heart failure, heart attack and stroke, within a year after being infected.
"That means it's likely that for every 100 people with COVID, there are four people who will develop some major cardiovascular event as a result of COVID up to a year out of the infection," Al-Aly said. "People say 'oh 4 percent, what's the big deal?' Well, many millions of people in the US have had COVID and that translates into many people in the U.S. who are either having or will have serious heart problems, and I think that's really that's really profound."
According to the Centers for Disease Control and Prevention (CDC), there have been 77.1 million cases of COVID-19 in the U.S. as of February 9, 2022. More disconcertingly, the researchers found that people who were infected with COVID-19 faced a 72% higher risk of heart failure, 63 % higher risk for a heart attack, and 52 percent for a stroke, compared to those who didn't test positive.
Notably, 99.7% of infected veterans studied were unvaccinated; therefore, the paper doesn't address whether long-term cardiovascular problems may occur after breakthrough infections in vaccinated people.
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The results of the paper have shocked other researchers in the field.
"Stunning … worse than I expected, for sure," Eric Topol, a cardiologist at Scripps Research, told Science magazine. "All of these are very serious disorders. … If anybody ever thought that COVID was like the flu, this should be one of the most powerful data sets to point out it's not."
But could other factors be at play that increased the risk in the individuals who were monitored in the study?
Al-Aly told Salon that researchers were careful to control for such factors.
"We took people who had COVID-19 and followed them for a year and compared them to people who had similar characteristics, but did not get COVID-19," Al-Aly says. "We adjusted for age and race and sex and all the other things, obesity and diabetes and all of that." In the end, Al-Aly says that the increased risk of heart disease is attributable solely to COVID-19.
As Topol alluded to, this study adds to a body of evidence that COVID-19, the disease caused by the novel coronavirus SARS-CoV-2, is not like a mild flu or cold. Rather, in many ways it resembles a cardiovascular disease; as Salon previously reported, research from 2020 suggested that the coronavirus may be a blood vessel disease in addition to a respiratory infection.
"In certain individuals COVID appears to trigger an inflammatory response that increases the risk for cardiovascular disease," said Dr. Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security. Adalja said there was clear evidence that "systemic inflammation" of the kind caused by COVID-19 can "negatively impact the cardiovascular system."
More researchers and doctors are starting to come around to the idea that COVID-19 isn't merely a respiratory disease, or a cardiovascular disease, but instead a systemic one that affects multiple systems in the body. Indeed, there have even been cases of patients developing diabetes after a Covid infection.
"It's a systemic virus that can actually result in long-term manifestations on multiple organ systems," including the heart and kidneys, Al-Aly said. "It's important for people to start thinking about COVID-19 being a risk factor for a serious cardiovascular event."
Al-Aly added that while diabetes is generally noted as a higher risk for a heart attack or stroke, the same should be true for people who have survived COVID-19.
"A history with COVID is certainly a cardiovascular risk factor, and I think people need to start thinking about it from that angle," Al-Aly said.
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