Flu increases risk of heart attack, new study finds

Researchers say influenza infection significantly increases the risk of heart attack, particularly in older persons.

A new Canadian study found that risk was six times higher in the first week after flu is diagnosed.

The researchers examined about 20,000 Ontario adult cases of laboratory-confirmed influenza infection from 2009 to 2014 and identified 332 patients who were hospitalized for a heart attack within one year of flu diagnosis.

Of the patients examined, 20 had a heart attack within a week of getting the flu and six ultimately died.

The researchers found a significant link between acute respiratory infections and acute myocardial infarction.

“Our findings are important because an association between influenza and acute myocardial infarction reinforces the importance of vaccination,” said lead author Jeff Kwong, a scientist at the Institute for Clinical Evaluative Sciences (ICES) and Public Health Ontario (PHO).

“People at risk of heart disease should take precautions to prevent respiratory infections, and especially influenza, through measures including vaccinations and handwashing,” said Kwong.

The researchers advised patients not to waste time on medical evaluation for heart symptoms, especially within the first week of an acute respiratory infection.

The study was published in the New England Journal of Medicine.