A new study that includes nearly 12 million patients have found that COVID-19 causes severe long-term cardiovascular risks. This is convincing evidence that everyone who can get vaccinated should get vaccinated or boosted.
Let’s take a look at the study and find out what it says about COVID-19 and cardiovascular disease.
The COVID-19 cardiovascular risk study
In an article by Yan Xie and colleagues in the Department of Clinical Epidemiology at Washington University School of Medicine, published in Nature Medicine, the researchers examined the incidence of 20 pre-determined serious cardiovascular diseases and outcomes over the course of a year in three different cohorts of USA military veterans.
The study utilized a massive database of health records at the Department of Veterans Affairs which has extensive medical history data from patients at 1255 healthcare facilities across the USA. The researchers focused on 153,760 veterans who tested positive for COVID-19 between 1 March 2020 and 15 January 2021. They surveyed these veterans at least 30 days after a COVID-19-19 diagnosis.
They compared this cohort to a control cohort of 5.6 million veterans from the same time period who did not test positive and to another control cohort of 5.9 million veterans from 2017 (who would have no chance of contracting COVID-19).
Using this data, the authors estimated risks and 1-year burdens of a set of pre-specified incident cardiovascular outcomes. The following cardiovascular conditions were tracked:
- Transient ischemic attack
- Atrial fibrillation
- Sinus tachycardia
- Sinus bradycardia
- Ventricular arrhythmias
- Atrial flutter
- Acute coronary disease
- Myocardial infarction
- Ischemic cardiomyopathy
- Heart failure
- Non-ischemic cardiomyopathy
- Cardiac arrest
- Cardiogenic shock
- Pulmonary embolism
- Deep vein thrombosis
- Superficial vein thrombosis
That list pretty much covers the breadth of cardiovascular diseases. And the results of this study were remarkable and a bit frightening:
- Overall, a COVID-19 infection significantly increased the risks of developing various cardiovascular diseases for 12 months afterward compared to individuals who were not infected.
- Individuals infected with COVID-19 had a 63% greater risk of developing any of those 20 cardiovascualar diseases over the year after infection compared to the uninfected cohort.
- The researchers estimated that there were 45 addtional individuals with any of those 20 coardioavacular diseases per 1000 people at the end of the year compared to the uninfected cohort.
- For heart attack, stroke, and cardiovascular death, those infected with COVID-19 had a 55% higher risk compared to the control groups.
- There were 23 extra cases of heart attack, stroke, and cardiovascuar death per 1000 compared to controls.
- Veterans with COVID-19 had a 72% higher risk of developing heart failure in the 12 months following their infection compared to the control cohorts.
- Infected veterans also had a range of 53-84% greater risk of developing one of the five arrhythmias compared to the control groups.
- Individuals who had COVID-19 had a 71% higher risk of developing atrial fibrillation.
- Individuals who had COVID-19 had a 52% greater risk of stroke, 63% higher risk of heart attack, 300% higher risk of pulmonary embolism.
- And here is something very important — individuals who had COVID-19 had a 500 times higher risk of myocarditis compared to the control group. The researchers did two additional analyses to elminate any possibility that vaccination status was a confounding variable. I will discuss this in more detail later, since it is a point of contention about some of the COVID-19 vaccines.
- The researchers also divided the study population into subgroups based on age, race, sex, obesity, smoking, hypertension, diabetes, chronic kidney disease, hyperlipidemia, and cardiovascular disease, in an attempt to rule out other confounding variables. The study authors concluded that the higher risks of cardiovascular outcomes were “evident in all subgroups.”
- The researchers also found that the cardiovascular risks “were also evident in people without any cardiovascular disease before exposure to COVID-19, providing evidence that these risks might manifest even in people at low risk of cardiovascular disease.”
- The researchers also examined cohorts based on care settings — not hospitalized, hospitalized, and intesive care. They found that although risks increased with the level of care, they found higher risks of cardiovascular disease even in those who never needed hospitalization before being infected.
- One concern, addressed by the authors, of this study is that it is a somewhat biased population — Veterans Administration patients tend to be older, male, and white. However, the data did not find any reduction in risk when examining subgroups that elminated these issues.
The authors concluded:
Governments and health systems around the world should be prepared to deal with the likely significant contribution of the COVID-19 pandemic to a rise in the burden of cardiovascular diseases. Because of the chronic nature of these conditions, they will likely have long-lasting consequences for patients and health systems and also have broad implications on economic productivity and life expectancy.”
This was a robust and rigorous evaluation of a large population of individuals who were infected and not infected by COVID-19. They found statistically significant large increases in risks of 20 cardiovascular diseases in those who had contracted COVID-19. If this doesn’t convince someone to receive the COVID-19 vaccine (even as the pandemic seems to be waning, although I wouldn’t bet on that), I don’t know what will convince them. I am almost willing to give up at that point.
And one more thing. The analysis of the risk of myocarditis, which has been associated with COVID-19 vaccines, tells us something important. The risk of myocarditis, a condition that resolves within a few days or weeks, after COVID-19 vaccination runs about 0.213 per 10,000 individuals, or as high as 1.07 per 10,000 in younger males. This study found that additional risk, over the uninfected population was about 0.31 per 10,000.
It is usually not appropriate to compare one study’s results to another (because of different methodologies and other issues), so the important point is that in this study the risk of myocarditis is 5X for the infected versus the control population. This clearly indicates that myocarditis risk is higher in those who contract COVID-19 compared to those who have not been infected. This does not mean there is no risk of myocarditis with the vaccine, it’s just the risk of getting it from the disease itself is much worse.
Of course, this type of study does not show causation. It is a powerful cohort study that does show a significantly increased risk for 20 different cardiovascular diseases in those who contract COVID-19. But it cannot show causation.
Right now, we don’t know why COVID-19 causes this. It’s possible that the virus directly infects the cardiac tissue. Or it may cause some sort of inflammation that leads to these outcomes. And the study did not separate out differences in COVID-19 variants, which may have shown which variant was the most serious.
But at this time, this study clearly shows a difference between large infected and uninfected populations. This study is powerful enough to establish that the risk is real and unfortunate.
Get vaccinated. It could save you from a lifetime of disease.
- Witberg G, Barda N, Hoss S, Richter I, Wiessman M, Aviv Y, Grinberg T, Auster O, Dagan N, Balicer RD, Kornowski R. Myocarditis after Covid-19 Vaccination in a Large Health Care Organization. N Engl J Med. 2021 Dec 2;385(23):2132-2139. doi: 10.1056/NEJMoa2110737. Epub 2021 Oct 6. PMID: 34614329; PMCID: PMC8531986.
- Xie Y, Xu E, Bowe B, Al-Aly Z. Long-term cardiovascular outcomes of COVID-19. Nat Med. 2022 Feb 7. doi: 10.1038/s41591-022-01689-3. Epub ahead of print. PMID: 35132265.