Dr-Eric Chow

Influenza Likely Contributes to Cardiac Events During Flu Season

MedicalResearch.com Interview with:

Dr-Eric Chow

Dr. Eric Chow

Eric J. Chow, MD, MS, MPH
Epidemic Intelligence Service Officer (completed in 2020);
Influenza Division.
Centers for Disease Control and Prevention 

MedicalResearch.com: What is the background for this study? What are the main findings?

  • Both heart disease and influenza epidemics cause substantial morbidity and mortality every year. In some seasons, influenza virus infections alone contribute up to 810,000 hospitalizations and 61,000 deaths. There is increasing evidence that there is overlap between infections, specifically influenza, and heart disease. In our study, we sought to describe the frequency and risk factors for acute cardiac events in patients who are hospitalized with influenza.
  • In over 80,000 adults hospitalized with influenza over 8 seasons (2010-2018), almost 12% were diagnosed with acute cardiac events, with acute heart failure and acute ischemic heart disease being the most common.
  • Among patients hospitalized with influenza who experienced acute cardiac events, almost one-third were admitted to the intensive care unit and 7% died while hospitalized.
  • Our study also reaffirmed that people who are older, smoke tobacco or have underlying cardiovascular disease, diabetes and kidney disease are at increased risk for the most common acute cardiac events, acute heart failure and acute ischemic heart disease.
  • Although vaccinated persons had a lower risk of acute ischemic heart disease and acute heart failure, this study was not designed to specifically assess vaccine effectiveness.  However, this and other studies support the importance of influenza vaccines for people with underlying heart conditions. 

MedicalResearch.com: What should readers take away from your report?

Response: While people are aware of respiratory complications associated influenza, our study shows that influenza is also commonly associated with acute cardiac events. Flu is one of the few respiratory viral infections that we have a vaccine for. The best way to protect against influenza and its complications is to ensure patients receive the flu vaccine every year. 

MedicalResearch.com: What recommendations do you have for future research as a result of this work?

  • While we describe the in-hospital outcomes of patients with influenza and acute heart disease, it would be important to understand what happens to people after they are discharged from the hospital. This would help answer questions such as how many of these patients are readmitted soon after discharge, or how many patients die in the period after discharge from the hospital.
  • Given this was a retrospective study which relied on clinical testing for diagnosis of influenza, there was likely under-detection of influenza cases and acute cardiac events among those with influenza. Future prospective studies with systematic influenza testing among persons hospitalized with acute cardiac events during the flu season, may better help to define the under-recognized burden of influenza in this population.
  • We know that flu vaccination is the best way of protecting against the adverse outcomes of infection, and maintaining high rates of influenza vaccination, especially those with risk factors, can prevent influenza-related complications. While this study showed that vaccinated patients had a lower risk of acute ischemic heart disease and acute heart failure, it was not designed to assess vaccine effectiveness. An area of future research is influenza vaccine effectiveness in patients with risk factors for acute heart disease, which would add to our understanding of influenza vaccine effectiveness in specific sub-populations of patients.

 MedicalResearch.com: Is there anything else you would like to add?

  • Influenza likely contributes to an under-recognized burden of heart-associated health events during the influenza season. It is important for clinicians to consider the respiratory and non-respiratory complications of influenza and other respiratory viral infections especially when speaking to their patients about the benefits of annual influenza vaccination.
  • I have no disclosures. 


Acute Cardiovascular Events Associated With Influenza in Hospitalized Adults

Eric J. Chow, Melissa A. Rolfes, Alissa O’Halloran, Evan J. Anderson, Nancy M. Bennett, Laurie Billing, Shua Chai, Elizabeth Dufort, Rachel Herlihy, Sue Kim, Ruth Lynfield, Chelsea McMullen, Maya L. Monroe, William Schaffner, Melanie Spencer, H. Keipp Talbot, Ann Thomas, Kimberly Yousey-Hindes, Carrie Reed, and Shikha Garg

Annals of Internal Medicine 0 0:0

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Last Updated on August 25, 2020 by Marie Benz MD FAAD