Congenital heart defects may not increase severe Covid-19 risk: Study

Adults and children born with heart defects had a lower-than-expected possibility of developing moderate or severe Covid-19 symptoms, according to a new study which cautioned that elderly patients with similar congenital conditions might have a different risk profile.

The scientists, including those from the Columbia University Irving Medical Center performed a retrospective analysis of more than 7,000 patients from the congenital heart disease center at the Vagelos College of Physicians and Surgeons in the US.

According to the study, published in the Journal of the American Heart Association, only 53 congenital heart patients (43 adults and 10 children) -- less than 0.8 per cent of patients at the heart center -- presented to their physician with symptoms of novel coronavirus infection from March through June.

The scientists said more than 80 per cent (43) of these patients had mild symptoms, nine developed moderate to severe symptoms, and three patients died.

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"At the beginning of the pandemic, many feared that congenital heart disease would be as big a risk factor for severe Covid-19 as adult-onset cardiovascular disease," said study co-author Matthew Lewis.

"We were reassured by the low number of congenital heart patients who required hospitalisation for Covid-19 and the relatively good outcomes of these patients," Lewis said.

During the study period, the scientists said an estimated 20 per cent of people in the the New York metropolitan area in the US are thought to have been infected with the coronavirus.

The researchers found that patients with a genetic syndrome and adults with advanced disease from their congenital heart defect were more likely to develop moderate to severe symptoms, though an individual's type of congenital heart defect did not impact symptoms severity.

Though the study sample was small, the scientists believe congenital heart disease alone may not be enough to increase the risk of severe Covid-19 symptoms.

Citing the limitations of the conclusions drawn from the study, the researchers hypothesise that the patients may have adhered more strictly to social distancing guidelines compared with the general population, given the publicity about increased Covid-19 risk in patients with heart disease.

They cautioned that individuals with congenital heart disease should continue to practice strict social distancing and follow all CDC guidelines as these measures are likely contributing to the study findings.

The younger average age (34 years) of these patients and lower incidence of acquired cardiac risk factors compared with other individuals who had severe Covid-19 may explain why fewer congenital heart patients than expected had severe symptoms, the study noted.

"It's possible that elderly patients with congenital heart disease might have a different risk profile than the general population," said Brett Anderson, another co-author of the study from Columbia University.

"We have yet to define what those risk factors are," Anderson added.