A disturbing report recently published on Medicine of Nature suggests that even a mild case of COVID can increase the long-term risk of serious cardiovascular disease such as stroke, heart attack and heart failure. The study highlights our limited understanding of the full implications of COVID infection and the long-term consequences of the COVID pandemic.
Australia has now reported over 10 million cases of acute COVID infection and over 14,000 deaths, while at least another 600 million people around the world are infected.
The immediate effects of COVID infection on the heart are well documented, with myocarditis (inflammation of the heart muscle) being a rare but potentially fatal complication. But myocarditis occurs in only about 40 people per million infected.
The main concern raised by this new study is that medium- and long-term damage to the body’s blood vessel network (the vascular system) is much more common than that. And that could trigger another cardiovascular disease pandemic in the coming years.
The study, led by University of Washington researchers, showed an increased risk of future cardiovascular events in people who have recovered from COVID.
The authors analyzed the medical records of approximately 150,000 U.S. veterans, who are often studied because they are a well-documented group within a discrete healthcare system. They compared the rates of cardiovascular disease in veterans who had experienced COVID infection with uninfected control groups that included approximately 10 million people.
Between 30 days and a year after recovering from COVID, survivors were 52% more likely to have a stroke, 63% more likely to have heart attack, and 72% more likely to have heart failure. This means that in a year, for every 1,000 people who have had COVID, there would have been five more strokes, three more heart attacks, and 12 more cases of heart failure. There was also evidence of an increased risk of severe blood clots in the lungs.
While these numbers may seem small to some, the implications are huge when they scale to 600 million COVID infections worldwide.
A particularly disturbing finding was that while those with more severe acute COVID infections were most at risk for cardiovascular events the following year, those with mild infections were also at greater risk. And that risk wasn’t limited to those who had previously had heart problems – it could affect anyone.
Observational study
The study was large and had many strengths. But the results should be viewed with some caution. It was an observational study (in which researchers draw conclusions from what they see in a population, rather than checking variables for an experimental study). So we can’t be sure that the increased risk of cardiovascular disease or stroke was definitively caused by the COVID infection. People infected with COVID were not identical to those not infected.
However, the researchers made statistical adjustments and could find no other explanation for the large increase in risk.
It is also likely that some people with asymptomatic COVID infection were accidentally included in the control groups. However, this would have led to underestimating the risks of COVID infection on cardiovascular risk.
And, of course, American veterans are a very special group of individuals (usually older, male, and white). While the effects of COVID on cardiovascular risk for them are real, there must be some uncertainty that the same effects would be seen in other populations.
The clear, but low, risk of heart disease at the time of COVID infection also provides support for a medium- and long-term link between COVID infection and heart disease.
Even before the COVID pandemic, there was a proven link between inflammation caused by infection and the risk of heart attack.
Vaccination rate
A heart attack occurs when an artery that supplies blood to the heart is blocked and the heart muscle is deprived of oxygen. This usually happens when a fat breaks down plate causes a blood clot in the artery. This process is driven by tissue inflammation and blood thickening, both of which can occur with COVID and both can persist long after the initial infection has cleared.
These data are a further reminder of the importance of limiting the spread of the SARS-CoV-2 virus. The best way to reduce the risks associated with COVID is to prevent COVID infection and reduce the severity of the infection.
We need to keep vaccination rates high and support infection control measures such as wearing a mask in high-risk situations. The growing evidence of the long-term effects of COVID makes the importance of these efforts even greater.
We rightly feared the respiratory complications of COVID in 2020 and 2021, but only now are we seeing the full effect of the pandemic on other body systems.
New long-term risk factor
Doctors will need to consider COVID infection as a new long-term risk factor for cardiovascular disease, just as many other chronic inflammatory diseases such as rheumatoid arthritis are now seen. We must support equal access to cardiovascular disease prevention and treatment for all Australians, especially those most at risk. Above all, as patients, we prioritize our heart health.
And we must remain vigilant for the effects of the new viral strains. Over the next few decades, we need to consider the lasting effects of COVID.
The conversation via Reuters.
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