The impact of influenza vaccination in patients with cardiovascular disease: An overview of systematic reviews.

Whether influenza vaccination can play a prognostic role in patients with cardiovascular (CV) disease (coronary artery disease (CAD), heart failure, stroke, peripheral artery disease (PAD)) is still not completely well-established. We conducted this overview of systematic reviews (SR) evaluating the effects of influenza vaccination in secondary prevention of CV disease. An electronic search was performed in the MEDLINE (to November 2019). Eligibility criteria included SR evaluating the effect of influenza vaccination in patients with CV disease. The risk of bias of the included systematic reviews was evaluated using the ROBIS tool. All-cause mortality, CV mortality, major adverse cardiovascular events (MACE) and hospitalizations were evaluated. Whenever required, data were recalculated through a random-effects meta-analysis to obtain pooled data for the patients at secondary CV prevention. The search process yielded four SR: two in CAD, one in heart failure and one in stroke. There were no SR evaluating the vaccine in PAD. The risk of bias was unclear (2 SR) and high (2 SR). Influenza vaccination in patients with CAD showed a risk reduction in all-cause mortality (data recalculated), cardiovascular mortality and MACE, particularly in patients with recent acute coronary syndrome. In patients with heart failure, vaccination was associated with a decreased risk of all-cause mortality. There was a non-significant trend in recurrent stroke risk reduction in patients with previous stroke. The available evidence suggests that influenza vaccination was associated with a protective effect in CAD and HF patients. However, these results need to be clarified with higher quality evidence studies.