Getting sick with the flu appears to increase a person's risk of having a heart attack by sixfold, especially among the elderly aged 65 and up, a new study has found.
Scientists have always linked the influenza virus with cardiovascular deaths. However, this connection has not been fully explored, as most patients who experience flu-like symptoms opt to self-medicate without testing for the virus.
In the study published last Wednesday in the New England Journal of Medicine, a Canadian research team reports their findings after analyzing hospital records and laboratory test results for influenza and other virus types.
According to its lead author, Dr. Jeff Kwong of Public Health Ontario, a flu patient faces a higher risk of heart attack particularly during the week after being diagnosed with the infection than a year before and after the diagnosis.
While the influenza virus brings the most amount of risk, the team were surprised to discover that other respiratory viruses such as rhinoviruses and adenoviruses have the same effect but only to a lesser extent.
Connecting Acute Myocardial Infarction With Seasonal Flu
To come up with this conclusion, Kwong and other scientists examined nearly 20,000 laboratory-confirmed cases of flu among adults from 2009 to 2014.
Based on these records, they identified 332 patients who were admitted to the hospital due to a heart attack a year before and after their flu diagnosis. Out of this population, 20 patients suffered a heart attack within a week of testing positive for influenza.
Specifically, 75 percent of these 20 patients were aged 65 and older, while 25 percent have already experienced a prior heart attack. Around one-third of these patients died.
Lowering Risk Level Through Annual Flu Vaccination
More significantly, the study revealed that 31 percent of all the heart attack patients missed their annual flu shots. While this data highlights the importance of immunization, Kwong stressed it must be interpreted carefully.
He emphasized that influenza vaccination does not necessarily provide a hundred percent protection against the infectious disease. A person who has been immunized even on a yearly basis can still contract the virus and be put at higher risk of heart attack.
Nonetheless, Kwong advised that getting immunized for the flu is still a good idea, as it reduces one's chances of having a heart attack by preventing infection.
CDC Associates Influenza With Heart Disease
The Centers for Disease Control and Prevention has previously warned those with heart disease about developing severe complications from influenza.
During the 2015-2016 flu season, it ranked as the most common condition among adult patients admitted in hospitals, with 41 percent of all adult flu patients possessing a prior record of heart disease.
The CDC recommends heart disease patients to get a flu shot each year. It is approved as safe for their health condition and has been linked to reduced rates of some coronary events.