NUDGE-FLU: What Interventions May Increase Vaccination Rates in Heart Failure Patients

Previous registry-based research has suggested that influenza vaccination rates are suboptimal across many cardiovascular diseases. Presented at ESC HFA 23 by Prof Niklas Dyrby Johansen, The NUDGE-FLU trial sought to identify effective strategies for increasing influenza vaccination rates among individuals aged 65 years and above in a large Danish population allowing for investigation into several subgroups, including heart failure and other cardiovascular-related diseases.


The trial included a total of approximately 965,000 eligible participants during the influenza season randomized into a usual care group and intervention group. The intervention group received one of nine different ‘nudging’ letters, each testing different approaches to encourage influenza vaccination. The primary endpoint was the receipt of an influenza vaccination, assessed on January 1 of the study year (2023).1


Among those aged 65 years and above, the vaccination rate was over 80%, and within the NUDGE-FLU heart failure subgroup, it reached 83%. Prof Niklas Dyrby Johansen also observed; “In the NUDGE-FLU heart failure subgroup, [the vaccination rate] was 83%. What we saw in the heart failure subgroup was that those who did not receive that much medical therapy for their heart failure were also those who were less likely to obtain influenza vaccination. So that just highlights a big implementation gap in those patients.”2.


Additionally, it was found that heart failure patients receiving less medical therapy were less likely to receive influenza vaccination, underscoring an implementation gap in this population.


The heart failure subgroup comprised 33,000 participants, representing a substantial portion of the trial population. Two letters showed consistent effectiveness in the heart failure subgroup: one that highlighted the potential cardiovascular benefits of vaccination, emphasizing reduced risk of heart attack or heart failure, and another standard letter sent at baseline and repeated on day 14.


The clinical significance of this data suggests that providing information on the potential cardiovascular benefits of influenza vaccination could be an effective strategy for clinicians to increase vaccination rates. A multidisciplinary approach, involving cardiologists, general practitioners, and other healthcare professionals, could further enhance vaccination efforts. The findings also highlight the underutilization of the influenza vaccination amongst younger heart failure patients, suggesting the clinical need for targeted interventions and increased emphasis on this age group.


Overall, the NUDGE-FLU trial provides valuable insights into the importance of increasing uptake of preventative influenza vaccinations in populations with heart failure, highlighting the need for targeted strategies and collaborative efforts to improve these rates.


1. Johansen, ND, Vaduganathan, M, Bhatt, AS, et al. Electronic nudges to increase influenza vaccination uptake in Denmark: a nationwide, pragmatic, registry-based, randomised implementation trial. The Lancet 2023;401:10382:1103-1114.

2. Radcliffe Cardiology, Niklas Dyrby Johansen. HFA 23: NUDGE-FLU: Increasing Influenza Vaccination in HF Patients. 2023. [Accessed 22.05.2023]

Article written by Jordan Rance