Heart attack risk is up to six times higher in people recently diagnosed with the flu, finds a study conducted by researchers at the Institute for Clinical Evaluative Sciences and Public Health Ontario, Canada, and published in The New England Journal of Medicine.
The Canadian researchers analyzed 19,729 adult cases of laboratory-confirmed flu from 2009 to 2014 in Ontario, focusing on 332 people, most over 65, who had been hospitalized for a heart attack within a year of their flu diagnosis. The researchers reported that there were 20 hospital admissions for heart attack per week during the seven days after a flu diagnosis – which appears to be the period in which people with flu are at highest risk of heart attack. In comparison, there were only 3.3 admissions for heart attack per week during the rest of the year.
This study is the first to use laboratory test results to confirm the link between influenza and heart attack risk – a link that had been observed in earlier studies.