Thursday, March 22, 2018

Eur. Resp.J.: Influenza & Pneumonia Infections Increase Risk Of Heart Attack and Stroke


For the past several years we've watched as a growing body of evidence has linked influenza and other respiratory infections to heart attacks and other cardiovascular incidents - particularly in the week following onset of infection.
While in January of this year, in NEJM: Acute Myocardial Infarction After Laboratory-Confirmed Influenza Infection, we looked at a report that found a `significant association' between recent (lab confirmed) influenza infection and Myocardial Infarction. 
In fact, they reported the odds of having a heart attack in the 7 days following influenza diagnosis went up 6-fold among the subjects in that study.
We've another study - published this week in the European Respiratory Journal - that also finds `substantially increased MI rates in the week after S.pneumoniae and influenza' while the risks of stroke was elevated for as much as 28 days.

First a link and the Abstract, followed by excerpts from a press release by the European Lung Foundation.
Laboratory-confirmed respiratory infections as triggers for acute myocardial infarction and stroke: a self-controlled case series analysis of national linked datasets from Scotland 
Charlotte Warren-Gash, Ruth Blackburn, Heather Whitaker, Jim McMenamin, Andrew C. Hayward 

European Respiratory Journal 2018; DOI: 10.1183/13993003.01794-2017


While acute respiratory infections can trigger cardiovascular events, the differential effect of specific organisms is unknown. This is important to guide vaccine policy.

Using national infection surveillance data linked to the Scottish Morbidity Record, we identified adults with a first myocardial infarction (MI) or stroke from 01/01/2004 to 31/12/2014 and a record of laboratory-confirmed respiratory infection during this period. Using self-controlled case series analysis, we generated age- and season-adjusted incidence ratios (IR) for MI (n=1,227) or stroke (n=762) after infections compared to baseline time.

We found substantially increased MI rates in the week after S.pneumoniae and influenza: adjusted IRs for days 1–3 were 5.98, 95% CI 2.47–14.4, and 9.80, 95% CI 2.7–40.5, respectively.
Rates of stroke after infection were similarly high and remained elevated to 28 days: day 1–3 adjusted IRs 12.3, 95% CI 5.48–27.7, and 7.82, 95% CI 1.07–56.9, for S.pneumoniae and influenza. Although other respiratory viruses were associated with raised point estimates for both outcomes, only the day 4–7 estimate for stroke reached statistical significance.

We showed a marked cardiovascular triggering effect of S.pneumoniae and influenza, which highlights the need for adequate pneumococcal and influenza vaccine uptake. Further research is needed into vascular effects of non-influenza respiratory viruses.


Laboratory-confirmed respiratory infections are linked to strokes and heart attacks in a Scottish population

 From the European Lung Foundation:

Flu and pneumonia infections increase risk of having a heart attack and stroke

European Lung Foundation

People who have had flu or pneumonia may be six times more likely to suffer from a heart attack or stroke in the days after infection, according to new research published in the European Respiratory Journal [1].
The research, funded by the Academy of Medical Sciences, is the largest study to look at the risk of heart attacks and strokes due to specific respiratory infections. It found that several different organisms that cause respiratory infections also increase heart attack and stroke risk, including S. pneumoniae bacteria and influenza.
The researchers say that the findings suggest that getting vaccinated against these two infections could also have a role in preventing heart attack and stroke, along with preventing infection in the first place.
In general, 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 S.pneumoniae, the most common pneumonia causing bacteria, can also have harmful effects on the heart muscle.
The new research found that having flu or pneumonia increases the risk of having a heart attack for up to a week after infection, and the risk of having a stroke is increased for one month.
        (Continue . . . . )

As any paramedic, ER nurse, or doctor can tell you, heart attacks are more common during the winter than in the summer.

In fact, a 1998 study looked at the rate of heart attacks in the United States, and found that Acute Myocardial Infarctions (AMIs) run as much 53% higher during the winter months than than during the summer.
While cold weather combined with strenuous physical activity (like clearing snow from sidewalks) have often been blamed for this spike, even in balmy Southern California, studies have shown a 33% increase in heart attacks over the winter holidays.
Increasingly, the evidence points to a previously under appreciated side effect of our annual winter respiratory illness epidemic as being behind this increase in excess winter mortality.

All reasons why I am a proponent of getting the flu vaccine every year, and why I elected to take the Pneumovax 23 vaccine when it was offered by my doctor. 
While recommended for everyone over 65, the CDC has a long list of qualifying conditions (which includes smoking, diabetes, and a litany of immunocompromising conditions , etc.) for those under the age of 65.  
To see if you fall into any of these groups and should consider getting the vaccine, either visit the CDC's Pneumococcal Vaccination webpage or talk with your doctor.