People who have had the flu or pneumonia may be six times more likely to suffer from a heart attack or stroke

Wednesday, 28 March 2018

People who have had the flu or pneumonia may be six times more likely to suffer from a heart attack or stroke in the days after an infection, new research has suggested.

The study which is the largest of its kind to look at the risk of heart attack and stroke due to specific respiratory infections such as the flu and pneumonia, found that several of the different bugs that caused these infections also increased the risk of heart attack and stroke.

It also found that getting vaccinated against flu and pneumonia could have a role in preventing heart attack and stroke, along with preventing infection in the first place.

Respiratory infections are thought to increase the risk of heart attack and stroke by causing inflammation, which can lead to the development of blood clots. The influenza virus and the most common pneumonia causing bacteria, can also have harmful effects on the heart muscle.

For the study researchers analysed national infection surveillance data from the Scottish Morbidity Record and identified 1,227 adults with a first heart attack and 762 with a first stroke who also had a respiratory virus or bacteria infection at any time between 2004 and 2014.

They then investigated the number of heart attacks and strokes that happened immediately after a respiratory infection and compared this to the rate of these events at other periods of time in the same people.

The data showed that having a confirmed respiratory infection made people six times more likely to have a heart attack or stroke for three days after infection.

Lead researcher Dr Charlotte Warren-Gash, Associate Professor of Epidemiology at the London School of Hygiene and Tropical Medicine, UK, said: “For most young, healthy people, the risk of heart attacks and strokes occurring after a respiratory infection is low. This research is particularly relevant for those over the age of 65, as well as people with pre-existing heart diseases, as these groups are at higher risk of heart attacks and strokes.

“These groups are already recommended to have vaccinations against influenza and S.pneumoniae – the two bugs we found to be linked to the highest cardiovascular risk – but we know that vaccine uptake is not high among younger people with heart problems. Understanding that there is a link between these bugs and heart attacks and strokes is an added incentive to get those vaccinations.”

Dr Angie Brown, Medical Director with the Irish Heart Foundation said that this study confirmed what was known and seen in clinical practice that when patients are unwell with pneumonia there followed an increased risk of heart attack and stroke.

“The inflammatory response increases the bloods stickiness making clots more likely, there are probably also other contributing factors such as if the patient is dehydrated or has underlying heart disease,” Dr Brown explained.

“The study is important as it highlights in particular strep pneumonia and influenza as an increased risk of heart attack and stroke reiterating the importance of those who are vulnerable getting vaccinated against influenza and pneumococcal pneumonia,” she added.

This study was published recently in the European Respiratory Journal.