Effect of Flu Vaccination on Severity and Outcome of Heart Failure Decompensations.

Objective: To investigate the relationship of seasonal flu vaccination with the severity of decompensation and long-term outcomes of patients with heart failure (HF).
Methods: We analyzed 6147 consecutively enrolled patients with decompensated HF who presented to 33 Spanish emergency departments (EDs) during January and February of 2018 and 2019, grouped according to seasonal flu vaccination status. The severity of HF decompensation was assessed by the Multiple Estimation of Risk Based on the Emergency Department Spanish Score in Patients With Acute Heart Failure (MEESSI-AHF) + MEESSI scale, need of hospitalization and in-hospital all-cause mortality. The long-term outcomes analyzed were 90-day postdischarge adverse events and 90-day all-cause death. Associations between vaccination, HF decompensation severity and long-term outcomes were explored by unadjusted and adjusted logistic and Cox regressions by using 14 covariables that could act as potential confounders.
Results: Overall median (IQR) age was 84 (IQR = 77-89) years, and 56% were women. Vaccinated patients (n = 1139; 19%) were older, had more comorbidities and had worse baseline status, as assessed by New York Heart Association class and Barthel index, than did unvaccinated patients (n = 5008; 81%). Infection triggering decompensation was more common in vaccinated patients (50% vs 41%; P < 0.001). In vaccinated and unvaccinated patients, high or very-high risk decompensation was seen in 21.9% and 21.1%; hospitalization occurred in 72.5% and 73.7%; in-hospital mortality was 7.4% and 7.0%; 90-day postdischarge adverse events were 57.4% and 53.2%; and the 90-day mortality rate was 15.8% and 16.6%, respectively, with no significant differences between cohorts. After adjusting, vaccinated decompensated patients with HF had decreased odds for hospitalization (OR = 0.823, 95%CI = 0.709-0.955).
Conclusion: In patients with HF, seasonal flu vaccination is associated with less severe decompensations.
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