Influenza vaccination reduces hospitalization for heart failure in elderly patients with chronic kidney disease: A population-based cohort study

Background: Elderly patients with chronic kidney disease (CKD) are at a higher risk of hospitalization for cardiovascular diseases (CVD). Previous studies have reported the beneficial effects of the influenza vaccine in patients with CVD. However, the effects of influenza vaccination on the reduction of hospitalizations for heart failure (HF) in elderly patients with CKD remain unclear. Methods: This cohort study comprised elderly patients (≥55 years of age) with a recorded diagnosis of CKD (n = 4406) between January 1, 1999 and December 31, 2008. Each patient was followed-up until the end of 2008. The hazard ratio (HR) and 95% confidence interval (CI) for the association between the influenza vaccination and the first HF hospitalization were analyzed. In addition, the patients were categorized into four groups based on their vaccination status (unvaccinated and total number of vaccinations: 1, 2-3, and ≥ 4). Results: We found that elderly patients with CKD receiving influenza vaccination exhibited a lower risk of HF hospitalization (adjusted HR, 0.31; 95% CI, 0.26-0.39, p <0.001). The protective effects of influenza vaccination remained consistent regardless of the age group (55-64, 65-74, ≥75), sex, and influenza seasonality. When the patientswere stratified according to the total number of vaccinations, the adjusted HRs for HF hospitalizationwere 0.60 (0.47-0.77), 0.30 (0.23-0.41), and 0.10 (0.06-0.16) for patients who received 1, 2-3, and ≥ 4 vaccinations during the follow-up period, respectively. Conclusions: The results revealed that elderly patients with CKD receiving annual influenza vaccination are at a lower risk of HF hospitalization.