A bout of COVID-19 can take a hefty toll on the heart and blood vessels; people who recover from the infection have substantially higher risks of developing any of 20 serious cardiovascular disorders in the year following their recovery. Those disorders include heart failure, stroke, atrial fibrillation and other arrhythmias, myocarditis (inflammation of the heart), and blood clots in the lungs.
Cardiovascular risks increase with the severity of an infection—that is, people who need intensive care for COVID-19 face the highest cardiovascular risks. But, overall, the pandemic virus appears to be indiscriminate, wreaking havoc on cardiovascular systems and increasing risks in all groups of patients, from those with mild disease, to the young, to those without underlying conditions or pre-existing cardiovascular diseases.
That’s all according to an open-access study involving more than 11 million veterans published this week in Nature Medicine by researchers at the VA St. Louis Health Care System and Washington University in St. Louis.
The study tapped into a massive database of health records at the Department of Veterans Affairs, which has data from patients at 1,255 health care facilities across the US. The authors, led by clinical epidemiologists Yan Xie and Ziyad Al-Aly, focused on 153,760 veterans who tested positive for COVID-19 between March 1, 2020 and January 15, 2021 and survived at least 30 days afterward. They then assembled a comparison group of 5.6 million veterans from the same period who did not test positive and a historical comparison group that included health records from 2017 from an additional 5.9 million veterans.
Xie, Al-Aly, and coauthors then looked at the incidence of 20 pre-determined serious cardiovascular diseases over the course of a year in the three cohorts. They also calculated the excess burden of disease that linked with COVID-19.
Overall, a COVID-19 infection significantly boosted the risks of developing cardiovascular diseases for a year afterward, compared with people who were uninfected. More specifically, people infected with COVID-19 had a 63 percent higher risk of developing any of the 20 cardiovascular diseases over the year than their uninfected contemporary cohort. In terms of excess burden, that meant that among the infected there were 45 additional people with any of the 20 cardiovascular diseases per 1,000 people at the end of the year, compared with the uninfected cohort.
When the researchers focused on the most devastating outcomes—heart attack, stroke, and death—those infected with COVID-19 had a 55 percent higher risk of those major events, which worked out to about 23 extra such cases per 1,000 people.
Of course, people with COVID-19 had different relative risks depending on which of the 20 cardiovascular diseases researchers looked at. For instance, veterans with COVID-19 had a 72 percent higher risk of developing heart failure in the 12 months following their infection compared with uninfected people. Infected veterans also had a range of 53 percent to 84 percent higher risk of developing one of five arrhythmias. Among those disorders, people with COVID-19 had a 71 percent higher risk of developing atrial fibrillation. The infected also had a 52 percent higher risk of having a stroke, a 63 percent higher risk of a heart attack, and nearly three times the risk of pulmonary embolism (blood clot in the lungs).
Veterans infected with COVID-19 also had more than five times the risk of developing myocarditis, which is inflammation of the heart muscle. Because some COVID-19 vaccines are also linked to myocarditis, Xie, Al-Aly, and coauthors conducted two separate analyses to eliminate any possible contribution that vaccination could play in increasing risk. Both analyses held that COVID-19 alone could increase the risk of myocarditis.
While the large size of the study is a clear strength, the veteran population is not representative of the entire population. The groups in the study skewed white, male, and older (with mean ages in the low 60s). As such, Xie, Al-Aly, and coauthors did a series of adjustments, given known differences in risks among demographics. They also did a battery of control and sensitivity analyses, as well as subgroup analyses.
For instance, the researchers ran their analyses looking for things known to be linked to COVID-19—namely fatigue—and reproduced an association. They looked for things not known to be linked to COVID-19—such as melanoma—and didn’t find an association.
They also split their groups into subgroups based on age, race, sex, obesity, smoking, hypertension, diabetes, chronic kidney disease, hyperlipidemia, and cardiovascular disease. They concluded that the higher risks of cardiovascular outcomes were “evident in all subgroups.”
The 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 authors noted in their conclusion.
When they looked at care settings—that is, if people were not hospitalized, hospitalized, or admitted to intensive care—the researchers found that risks increased with needed care. But the higher risks of cardiovascular disease were still clearly evident in people who never needed hospitalization, which is the majority of people with COVID-19.
How the pandemic virus is causing these cardiovascular outcomes is still unknown. Researchers have myriad hypotheses, from indirect inflammation to direct viral invasion of heart tissue. It’s also unclear if different variants of the virus carry the same level of risks. For instance, the omicron coronavirus appears more confined to the upper respiratory tract and may cause milder disease overall. It’s unclear if it would carry the same cardiovascular risks as previous variants linked with more severe cases, such as delta.
But, regardless of the mechanism and variants, with the enormous number of people already infected, it is clear that cardiovascular outcomes from COVID-19 will have a major influence on health and health care systems in the years to come.
“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,” the authors caution. “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.”