Most of us who get Covid recover within a few weeks. But Long Covid, when symptoms last for months or more, is a reality for an estimated 400 million people worldwide. And there is growing evidence that the condition is damaging the hearts of those affected.
In a study recently published in The Lancet, researchers from the Karolinska Institute in Sweden found that people with Long Covid had a higher risk of developing cardiovascular disease – including cardiac arrhythmias, heart attack and heart failure. Of particular significance was that the increased risks were seen in people who had never been hospitalised during their initial Covid infection.
The study focused specifically on patients who had experienced a mild-to-moderate Covid infection which they managed at home. Using healthcare data from more than 1.2 million adults living in Stockholm, Sweden, researchers identified 9,000 people who were diagnosed by a doctor with Long Covid. They followed up these patients over time and compared the occurrence of new cardiovascular disease – including heart attack, heart failure, arrhythmias, stroke and peripheral arterial disease – with people who did not have Long Covid and had no previous cardiovascular disease.
After a follow-up period of up to four years, they found that cardiovascular disease was more common among people with Long Covid. Among women with Long Covid, 18 per cent experienced some form of cardiovascular event, compared with 8 per cent of women without Long Covid. Among men with Long Covid, 21 per cent had a cardiac event as against 11 per cent who did not experience Long Covid.
These results did not substantially differ when they adjusted analyses for age, socioeconomic status and underlying health status – including conditions such as high blood pressure, diabetes, high cholesterol, obesity, depression, smoking and alcohol consumption – which are known risk factors of cardiovascular disease.
Overall, women with Long Covid had more than double the risk of developing cardiovascular disease compared with women without Long Covid, while men had around a 30 per cent higher risk. The strongest associations were seen for irregular heart rhythm and coronary heart disease. In women, there was also an increased risk of heart failure and peripheral arterial disease. However, the study did not find an association between Long Covid and stroke risk.
The Swedish research confirms a 2022 study of almost 154,000 US veterans. Between 30 days and a year after Covid infection, these veterans had a greater risk of cardiovascular disorders – including arrhythmias, ischaemic heart disease, heart failure and stroke – than two control groups.
Which leads to the question: how does Long Covid affect the heart? While it’s not fully understood why Long Covid is associated with cardiovascular disease, several biological mechanisms have been proposed.
Researchers from the Karolinska Institute in Sweden have found that people with Long Covid have a higher risk of developing cardiovascular disease. Illustration: Getty Images
The inner lining of blood vessels – called the endothelium – while not directly infected by Long Covid, are affected by long-lasting inflammation and changes in the immune system. Together, these processes can affect how blood flows through the body and how the heart functions.
There is also growing evidence that Long Covid can disrupt the autonomic nervous system – including the automatic mechanisms that control heart rate and blood pressure. This potentially explains why irregular heart rhythms and conditions such as postural orthostatic tachycardia syndrome (Pots) are more common in Long Covid patients.
[ Long Covid to cost OECD economies up to €115bn a yearOpens in new window ]
The prospective Swedish research ties in with the lived experience of those with Long Covid. Chest pain, palpitations, shortness of breath and drop attacks are common in people with Long Covid.
Commenting on their study, the Swedish researchers say it suggests Long Covid is not simply a transient condition, even among people who were never severely ill during the acute infection. “Instead, it may have longer-term implications for cardiovascular health,” they say.
That we need to refocus on Long Covid is reinforced by a recent comment in the British Medical Journal from a vascular biologist, who said: “In many respects Covid-19 is a vascular disease masquerading as a respiratory one.”