Influenza vaccination rates vary widely in patients with HF – Healio

Influenza vaccination rates varied widely, especially by country, among patients with HF with reduced ejection fraction enrolled in the PARADIGM-HF trial. Vaccination in this population was associated with a reduced mortality risk, researchers reported in the Journal of the American College of Cardiology: Heart Failure.

In the PARADIGM-HF trial, researchers compared valsartan/sacubitril (Entresto, Novartis) to the ACE inhibitor enalapril and analyzed the effect on death and HF hospitalization in patients with HF with reduced ejection fraction (HFrEF). According to previously published findings, valsartan/sacubitril was superior to enalapril.

Using data from this trial, Scott D. Solomon, MD, director of noninvasive cardiology at Brigham and Women’s Hospital, and colleagues examined the associations between influenza vaccination and HF mortality, HF hospitalization, all-cause hospitalizations, and cardiopulmonary or influenza-related hospitalizations. The researchers also analyzed predictors for receiving influenza vaccination.

Of the 8,099 participants in the study, only 21% (n = 1,769) received an influenza vaccination within a 12-month period. By region, the Netherlands (77.5%), Great Britain (77.2%) and Belgium (67.5%) had the highest rates of vaccination among PARADIGM-HF participants. The lowest rates were found in Asia (2.6%). Participants in North America had a vaccination rate of 52.8%.

In propensity-adjusted models, the researchers found that the influenza vaccination was associated with a reduced risk for all-cause mortality (HR = 0.81; 95% CI, 0.67-0.97; P = .015). The vaccine did not alter the efficacy of valsartan/sacubitril.

Participants who were vaccinated were more likely to be white, older and have an implantable cardioverter defibrillator. Other predictors of vaccination included lower NYHA HF class, lower heart rate, and history of diabetes.

Although the researchers could not determine the reasons why vaccination rates were low, they suggested that accessibility, cost, lack of knowledge about the benefits, and wariness over the effectiveness and side effects could be possible factors.

Before adjustment, vaccinated participants had an increased risk of cardiopulmonary, influenza-related and all-cause hospitalization, but according to the researchers, “that influenza vaccination was associated with a higher unadjusted rate of hospitalization of any type, but not an increased risk of death, suggests that in PARADIGM-HF, influenza vaccination was a potential surrogate for higher level of and improved access to health care, evidenced by more hospitalizations, for any given severity of illness, among individuals who received influenza vaccine.”

Solomon and colleagues noted that although this study found an association, there were not enough data to determine a causal relationship between vaccination and reduced risk of death. Because the types of vaccines were not reported, the researchers also couldn’t assess which vaccine types were associated with better outcomes for patients with HF. – by Tracey Romero

Six researchers report receiving consultant fees or research funding from Novartis, sponsor of the PARADIGM-HF trial. Please see the full study for a list of all other authors’ relevant financial disclosures.