Researchers recently conducted a study to see how the flu shot affected the prognosis of patients with heart failure.
Influenza, more commonly known as “the flu”, has been known to cause serious harm in those with weak immune systems, including babies and the elderly, but also in those with diagnosed heart failure. There is limited knowledge about this association, so a cohort study was conducted in Denmark by Daniel Modin and colleagues to investigate whether an annual flu shot was associated with decreased risk of death due to cardiovascular events. They published their results in the journal Circulation.
They used the Danish National Patient Registry and identified 134 048 people who were newly diagnosed with heart failure between January 1st, 2003 and June 1st, 2015, checking to see which patients had vaccinations and how many. They also investigated how and when each patient died.
They found that patients who had the flu vaccine once or more had a lower risk of dying from any cause by 18%. These patients also had an 18% lowered risk of dying from a heart problem. There was an even larger reduction in the risk of death in those patients who had consistently gotten their annual flu vaccine, compared to those who had gotten one intermittently throughout the years.
This study was limited with information that was provided only through general practitioners, so the data of patients were vaccinated elsewhere was not included, or were classified as unvaccinated. There were also limitations through a lack of clinical variables and an undetermined reason for a significant increase in rates of vaccination from 2006 to 2008.
In conclusion, Modin and colleagues showed that the flu vaccine can decrease the risk of cardiovascular death, as well as death through various causes. The annual flu vaccine can be used as a strategy to improve the survival rate in those with heart failure.
Written by Unaisa Bhayat, BMedSc
References: Modin D., Jorgensen M. E., Gislason G., Jensen J. S., Kober L., Claggett B., Hegde S. M., Solomon S. D., Torp-Pedersen C., Biering-Sorensen T. Influenza Vaccine in Heart Failure. Circulation. 2018; 139: 00-00. DOI: 10.1161/CIRCULATIONAHA.118036788