Hospitalised COVID-19 patients with congenital heart defect may be at higher risk for severe illness or death than those without the disorder, according to a US study.

The research, published in the journal Circulation, found that people with a congenital heart defect who contracted COVID-19 were also more likely to require treatment in the intensive care unit (ICU) or need a ventilator.

The researchers found that among those at the highest risk for the most severe COVID-19 illness were patients who had a heart defect and another health condition, were 50 years and older, or were men.

There are more than a dozen types of congenital heart defects, which result when the heart, or blood vessels near the heart don’t develop normally before birth, they said.

“Data comparing COVID-19 outcomes among individuals with and without congenital heart defects has been limited,” said study lead author Karrie Downing from the U.S. Centers for Disease Control and Prevention.

Researchers examined data on hospitalised COVID-19 patients from March 2020 to January 2021, collected in the Premier Healthcare Database Special COVID-19 Release, a database representing approximately 20 per cent of all U.S. hospitalisations.

During this period, the database had more than 235,000 patients, aged 1 to 64 years old, who were hospitalised for COVID-19.

Patients were divided into two groups: those who had a congenital heart defect and those who did not.

Researchers then determined how many required an admission to the ICU, needed a ventilator to help with breathing or died.

They also reviewed other characteristics including other health conditions.

People with congenital heart defects consistently remained at high-risk for severe COVID-19 illness, even when divided into categories by age or other health conditions noted in the study, according to the researchers.

The findings have immediate, practical relevance for health care professionals as the COVID-19 pandemic continues to evolve, the researchers said.

“People with heart defects should be encouraged to receive the COVID-19 vaccines and boosters and to continue to practice additional preventive measures for COVID-19, such as mask-wearing and physical distancing,” said Downing.

“People with heart defects should also consult with their health care teams about additional steps to manage personal risks related to COVID-19, given the significantly increased risk of severe infection and serious complications,” she added.

Downing noted that not all patients with heart defects who were hospitalised with COVID-19 had poor outcomes.

The authors pointed out several limitations to their study.

Only people already hospitalised with COVID-19 were included, the clinical details about the underlying heart defect were not available, and lab testing to identify or confirm COVID-19 diagnoses may vary by hospital.

COVID-19 vaccination status was not considered, since the vaccines became available in the U.S. starting in December 2020.