Excess influenza deaths attributable to cardiovascular disease average 35 to 50 percent
THURSDAY, Sept. 24 (HealthDay News) -- For people with heart disease, getting influenza increases the risk of heart attack and death, and cardiac patients should be strongly encouraged to get vaccinated, according to a literature review and meta-analysis reported in the October issue of The Lancet Infectious Diseases.
Charlotte Warren-Gash, of the Royal Free Hospital in London, and colleagues conducted a review of the medical literature on influenza and influenza-like disease as a trigger for acute myocardial infarction and cardiovascular death. The reviewers screened 214 studies before conducting a full review and meta-analysis of the 39 studies judged most relevant.
The reviewers found that population studies consistently showed an increase in cardiovascular events in flu season and calculated that the proportion of excess deaths attributable to the flu averaged 35 to 50 percent. Observational studies found consistent associations between the flu and heart attacks. However, of the eight observational studies reviewed, four demonstrated a protective effect for those who got a flu vaccination. Further, results from two randomized trials, the 2004 FLUVACS study with 301 patients and the 2008 FLUCAD study with 658 patients, suggested that a flu vaccination can reduce the risk of cardiovascular death and some cardiac events.
"We believe influenza vaccination should be encouraged wherever indicated, especially in people with existing cardiovascular disease, among whom there is often suboptimum vaccine uptake. Further evidence is needed on the effectiveness of influenza vaccines to reduce the risk of cardiac events in people without established vascular disease," the authors write.
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