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Electronic Nudge and Flu Vaccination Rate in Older Adults With CVD
Quick Takes
- Two electronic letter strategies—a repeated letter with a reminder follow-up letter 14 days later and a letter emphasizing the potential CV benefits of influenza vaccination—improved vaccination rates in older adults with and without CVD.
- Select digital behaviorally informed nudges delivered in advance of vaccine availability might be utilized to increase influenza vaccine uptake in individuals with CVD.
- This proof-of-concept could set the stage for future studies using similar approaches to potentially increase uptake of guideline-directed medical therapy in major CVD subgroups such as heart failure or ischemic heart disease.
Study Questions:
What is the effect of digital behavioral nudges on influenza vaccine uptake based on the presence of cardiovascular disease (CVD)?
Methods:
The investigators conducted a randomized, pragmatic, nationwide, register-based trial including Danish citizens aged ≥65 years during the 2022-2023 influenza season. Households were randomized in a 9:1:1:1:1:1:1:1:1:1 ratio to usual care or nine electronic letters with designs based on behavioral concepts. Danish nationwide registers were used to collect baseline and outcome data. The primary endpoint was receipt of an influenza vaccine on or before January 1, 2023. The effects of the intervention letters were examined according to the presence of CVD and across CV subgroups including heart failure, ischemic heart disease, and atrial fibrillation.
Results:
Of 964,870 NUDGE-FLU participants from 691,820 households, 264,392 (27.4%) had CVD. During follow-up, 83.1% of participants with CVD versus 79.2% of participants without CVD received influenza vaccination (p < 0.001). Compared with usual care, a letter emphasizing the potential CV benefits of influenza vaccination increased vaccination rates; this effect was consistent in participants with CVD (absolute difference, +0.60 percentage points; 99.55% confidence interval [CI], -0.48 to 1.68) and without CVD (+0.98 percentage points; 99.55% CI, 0.27 to 1.70; p for interaction = 0.41). A repeated letter strategy with a reminder follow-up letter 14 days later was also effective in increasing influenza vaccination, irrespective of CVD (CVD: absolute difference, +0.80 percentage points; 99.55% CI, -0.27 to 1.86; no CVD: +0.67 percentage points; 99.55% CI, -0.06 to 1.40; p for interaction = 0.77). Effectiveness of both nudging strategies was consistent across all major CVD subgroups. None of the other seven nudging strategies were effective, regardless of CVD status.
Conclusions:
The authors report that electronic letter interventions emphasizing the potential CV benefits of influenza vaccination and using a reminder letter strategy were similarly beneficial in increasing influenza vaccination rates among older adults with and without CVD.
Perspective:
In this prespecified analysis of the NUDGE-FLU trial, two electronic letter strategies—a repeated letter with a reminder follow-up letter 14 days later and a letter emphasizing the potential CV benefits of influenza vaccination—improved vaccination rates in older adults with and without CVD and across various forms of CVD. Overall, these data suggest that select digital behaviorally informed nudges delivered in advance of vaccine availability might be utilized to increase influenza vaccine uptake in individuals with CVD. Furthermore, this proof-of-concept could set the stage for future studies using similar approaches to potentially increase uptake of guideline-recommended therapy in major CVD subgroups such as heart failure or ischemic heart disease.
Clinical Topics: Arrhythmias and Clinical EP, Geriatric Cardiology, Heart Failure and Cardiomyopathies, Prevention, Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure
Keywords: Atrial Fibrillation, Cardiovascular Diseases, Digital Technology, Geriatrics, Heart Failure, Influenza Vaccines, Influenza, Human, Myocardial Ischemia, Primary Prevention, Seasons, Vaccination
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