Influenza vaccination may lower risk for all-cause, CV death in patients with CVD
Among patients with CVD, influenza vaccination was associated with lower risk for all-cause and CV death and major adverse CV events compared with no vaccination, according to a meta-analysis.
Researchers reported no significant change in risk for MI.
“We found the benefits attributed to influenza vaccine were large — notably for mortality reduction which is the most important endpoint, and typically the hardest endpoint to achieve in trials,” Cardiology Today Editorial Board Member Erin D. Michos, MD, MHS, FACC, FAHA, FASE, director of Women’s Cardiovascular Health and associate director of preventive cardiology at the Ciccarone Center for the Prevention of Cardiovascular Disease at Johns Hopkins School of Medicine, told Healio. “We found influenza vaccination was associated with 25% and 18% relative risk reductions in all-cause and CV mortality, respectively, and a 13% reduction in major adverse CV events among patients with CVD.
“This is a substantial reduction in mortality given the safety, feasibility and cost efficiency of influenza vaccination, and thus vaccination should be considered alongside of other CV prevention therapies,” Michos told Healio. “The risk reduction we see with influenza vaccine is even greater than risk reduction we see for other types of preventive medications like beta-blockers and ACE inhibitors, and the influenza vaccine is just one shot per year, compared to taking medications every single day for the whole year. It’s a huge benefit.”
For the meta-analysis published in the Journal of the American Heart Association, researchers identified 16 trials (four randomized; 12 observational) that enrolled 237,058 participants (mean age, 69 years; 37% women) to evaluate the effects of influenza vaccination on mortality among those with CVD.
“There have been multiple postulated mechanisms that could explain an increased cardiovascular risk after influenza infection, including atherosclerotic plaque de-stabilization and subsequent thrombosis, deposition of immune complexes in atherosclerotic plaques, and elevation of macrophage circulation into the arteries resulting in coronary vascular events,” the researchers wrote.
Overall, 65.1% of the population had hypertension, 31.1% had diabetes and 23.4% were current smokers.
At a median follow-up of 19.5 months, researchers observed that influenza vaccination was associated with lower risk for all-cause mortality (RR = 0.75; 95% CI, 0.6-0.93; P = .01), CV mortality (RR = 0.82; 95% CI, 0.8-0.84; P < .001) and major adverse CV events compared with control (RR = 0.87; 95% CI, 0.8-0.94; P < .001).
However, influenza vaccination was not associated with lower risk for MI compared with control (RR = 0.73; 95% CI, 0.49-1.09; P = .12).
“Our study reiterates the survival benefit and CV risk reduction achieved with influenza vaccine in patients with CVD,” Michos told Healio. “Our findings may help health care professionals and policy makers to strongly advocate the influenza vaccination for secondary prevention of CV outcomes.
“Cardiologists are least likely of all medical professionals to stock the flu shot in their clinics, expecting patients to get their vaccination elsewhere,” Michos told Healio. “However, our meta-analyses findings confirm the influenza vaccine is very beneficial to cardiac patients, and if cardiologists are least likely to stock it, that’s a huge gap.”
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Erin D. Michos, MD, MHS, FACC, FAHA, FASE, can be reached at email@example.com.