Effectiveness and Safety of COVID-19 Vaccination in Patients With Heart Failure: A Nationwide Retrospective Cohort Study.

Background and objectives: We aimed to evaluate the efficacy and safety of coronavirus disease 2019 (COVID-19) vaccination in patients with heart failure (HF) using national databases.

Methods: We retrospectively analyzed the data from the Korean nationwide COVID-19 cohort, including patients with HF from February 2021 to June 2022. The study population was divided into the vaccinated (≥2 doses) and unvaccinated (≤1 dose) groups. Clinical outcomes assessed included hospitalization for HF, COVID-19-related events, and cardiovascular complications. Patients were matched by age, sex, and comorbidities, and were followed up for up to 15 months to assess vaccination-associated risks.

Results: We included 651,127 patients with HF (mean age 69.5 years; 50.2% male), of whom 112,693 (17.3%) were unvaccinated, and 538,434 (82.7%) were vaccinated. After propensity score matching, 73,559 patients in each group were compared. Over a median follow-up of 6 months, vaccination was associated with a significantly reduced risk of COVID-19 (hazard ratio [HR], 0.27; 95% confidence interval [CI], 0.22-0.33) and critical COVID-19 infection (HR, 0.47; 95% CI, 0.31-0.71). The vaccinated group also had a significantly lower risk of hospitalization for HF (HR, 0.53; 95% CI, 0.52-0.55) and all-cause mortality (HR, 0.18; 95% CI, 0.17-0.18) compared with the unvaccinated group. Additionally, vaccination was associated with a significantly lower risk of stroke, myocardial infarction, myocarditis/pericarditis, and venous thromboembolism compared with the unvaccinated patients (all, p<0.0001).

Conclusions: COVID-19 vaccination in patients with HF was associated with a reduced risk of hospitalization for HF, all-cause mortality, and other cardiovascular events.