Flu Season 2020: 1 in 8 Americans hospitalized with flu have sudden serious heart complications, warns study
The link between flu and serious heart conditions just became stronger. Sudden, serious heart complications are common among flu patients, occurring in about 12% of them, or 1 in 8, according to a large study that analyzed more than 80,000 adult patients hospitalized with flu over eight seasons. The analysis, funded by the US Centers for Disease Control and Prevention (CDC), underscores the importance of getting a flu shot early, say experts. The authors also found that 5% of patients hospitalized with the flu had a cardiac complication despite having no documented underlying conditions.
“Previous to our study, there had been suggestions between the link, but our study shows just how common it is. There are few respiratory viruses we have a vaccine for. Our team motto is ‘get a flu shot’,” recommends lead author Eric Chow, an infectious diseases fellow at the University of Washington School of Medicine. “One of the things that we need to do when we’re counseling our patients as physicians is to ensure that they know that the flu vaccine is going to protect them not just against the pulmonary manifestations, but potentially these other extrapulmonary complications of influenza,” adds Chow, who has previously worked as an epidemic intelligence service officer for influenza at the CDC.
According to the CDC, an estimated 1 in 10 Americans will become sick with flu in any given season, and some people are at increased risk of developing influenza-related complications. Adults 65 years and older, young children, and people with underlying health conditions such as heart disease, asthma, diabetes, HIV/AIDS, chronic kidney disease, among others, are considered to be high-risk groups.
For the current report, published in the Annals of Internal Medicine, the research team turned to the US influenza hospitalization surveillance network during the 2010-to-2011 through 2017-to-2018 influenza seasons. Adults hospitalized with laboratory-confirmed influenza and identified through influenza testing ordered by a practitioner were included in the analysis
Among 89,999 adults with laboratory-confirmed influenza, 80,261 had complete medical records (median age, 69 years), and about 12% had acute heart complications. Of these, 30% were admitted to the ICU and 7% died while in the hospital. “11.7% had an acute cardiovascular event. The most common such events (non–mutually exclusive) were acute heart failure (6.2%) and acute ischemic heart disease (5.7%). Older age, tobacco use, underlying cardiovascular disease, diabetes, and renal disease were significantly associated with a higher risk for acute heart failure and acute ischemic heart disease in adults hospitalized with laboratory-confirmed influenza,” the findings state.
In the US, flu season occurs in the fall and winter. While influenza viruses circulate year-round, most of the time flu activity peaks between December and February, but activity can last as late as May. The CDC recommends that everyone 6 months and older get a flu vaccine every flu season. According to the agency, flu vaccination is always considered important for people at high risk of developing serious flu complications, including people with heart disease. “Clinicians should ensure high rates of influenza vaccination, especially in those with underlying chronic conditions, to protect against acute cardiovascular events associated with influenza,” recommend authors.
Flu shots are approved for people with heart disease, but people with heart disease should not receive the live attenuated influenza vaccine (LAIV, also known as the nasal spray flu vaccine). However any intramuscular flu shot, such as any inactivated or recombinant influenza vaccine, would be appropriate, says the CDC.