June 27, 2023European Journal of Heart FailureOpen Access

Influenza Vaccination and Cardiovascular Events in Patients with Ischaemic Heart Disease and Heart Failure: A Meta-Analysis

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Why the study?

Randomized controlled trials in patients at high cardiovascular risk found that influenza vaccination may reduce cardiovascular events, prompting an updated meta-analysis in ischaemic heart disease or heart failure.

Does influenza vaccination reduce cardiovascular events in patients with ischaemic heart disease or heart failure?

Structured PICO

Does influenza vaccination reduce cardiovascular events in patients with ischaemic heart disease or heart failure?

Population

9,340 patients from 6 RCTs (5 trials with ischaemic heart disease n=4,211; 1 trial with heart failure n=5,129)

Intervention

Influenza vaccination

Comparator

Placebo or no treatment

Outcome

Composite of cardiovascular death, acute coronary syndrome, stent thrombosis or coronary revascularization, stroke or heart failure hospitalizationcomposite

In patients with ischemic heart disease or heart failure, influenza vaccination significantly reduces the risk of major cardiovascular events and mortality.

Implication

Supports influenza vaccination to lower CV events and mortality in IHD or HF patients; reinforces RCT evidence for risk reduction.

Abstract

Aim Randomized controlled trials (RCTs) enrolling patients at high cardiovascular risk have found that influenza vaccination may reduce the incidence of cardiovascular events. We performed an updated meta-analysis assessing the effect of influenza vaccination on the incidence of cardiovascular events in patients with ischaemic heart disease or heart failure. Methods and results We searched PubMed, EMBASE and other sources to identify RCTs examining the effect of influenza vaccination on the incidence of cardiovascular events assessed as efficacy outcomes in patients with ischaemic heart disease or heart failure. Eligible studies followed patients for at least one influenza season, defined as a minimum duration of 6 months. The primary endpoint was a composite of cardiovascular death, acute coronary syndrome, stent thrombosis or coronary revascularization, stroke or heart failure hospitalization. The secondary endpoints were cardiovascular death and all-cause death. Two investigators independently identified and extracted data from studies. Results were compared using hazard ratios (HRs) in both random effects and fixed effects models. We included five peer-reviewed and one non peer-reviewed RCTs for a total of 9340 patients. Five trials included patients with ischaemic heart disease (n = 4211) and one trial included patients with heart failure (n = 5129). Influenza vaccination was associated with a reduced incidence of the primary composite endpoint (random effects HR [rHR] 0.74, 95% confidence interval [CI] 0.63–0.88, p < 0.001, I2 = 52%), cardiovascular death (rHR 0.63, 95% CI 0.42–0.95, p = 0.028, I2 = 58%) and all-cause death (rHR 0.72, 95% CI 0.54–0.95, p = 0.0227, I2 = 52%). Results were similar when non peer-reviewed data were excluded. Conclusion In this meta-analysis of available RCTs in patients at high cardiovascular risk, influenza vaccination was associated with a reduced incidence of cardiovascular events, cardiovascular death and all-cause death as compared to placebo or no treatment.