Understanding NUDGLE-FLU Data from AHA 2024, with Ankeet Bhatt, MD, MBA, ScM

Use of emails highlighting the cardiovascular benefits of influenza vaccination could significantly increase the rate of vaccine uptake among adults with a history of myocardial infarction, according to a new analysis from the NUDGE-FLU program.

Presented at the American Heart Association (AHA) Annual Scientific Sessions 2024, results of the analysis demonstrate messaging highlighting the potential cardiovascular benefits of flu shots led to a 3.9% increase in vaccination among people with a history of heart attack compared to a 2% increase for those with no heart attack history, with results also providing insights into individual-level patient factors influencing rate of vaccine uptake.

“The data suggest that cardiovascular-focused messaging was effective across a broad population; this strategy should be considered as part of a suite of strategies to improve cardiovascular prevention and encourage flu vaccination among high-risk patients, including those with a history of heart attack,” said principal investigator Ankeet Bhatt, MD, MBA, SCM, a cardiologist at Kaiser Permanente San Francisco Medical Center, a research scientist at the Kaiser Permanente Northern California Division of Research, and an adjunct professor at the Stanford University School of Medicine. “Notably, this strategy alone did not close all implementation gaps for flu vaccination. Other strategies in addition to messaging-based intervention need to be tested to fully close this important prevention gap in at-risk patients.”

The NUDGE-FLU program, a groundbreaking initiative launched in Denmark evaluating the effectiveness of behavioral science-informed nudges delivered through government electronic communication systems for improving vaccination rates among high-risk populations. At the time of the AHA 2024 presentation, the program included 3 trials—NUDGE-FLU, NUDGE-FLU-2, and NUDGE-FLU-CHRONIC, which were conducted during the 2022-2023 and 2023-2024 influenza seasons and included a total of 2,146,124 participants.

The original NUDGE-FLU trial randomized 964,870 adults aged 65 and older to receive one of nine behavioral science-informed letters or usual care. NUDGE-FLU-2 involved 881,373 adults in the same age group, randomized to receive one of six behavioral science-informed letters or usual care. NUDGE-FLU-CHRONIC focused on 299,881 adults aged 18 to 64 with chronic conditions, using a similar design. Across all trials, 2.8% (n=59,458) of participants had a history of acute myocardial infarction.

Analysis indicated vaccine uptake improved for both those with and without this history who received any nudge letter compared to usual care (+1.81 vs. +1.32 percentage points, P = .09). Notably, the letter emphasizing the cardiovascular benefits of vaccination yielded greater increases in uptake among those with a history of acute myocardial infarction (+3.91 vs. +2.03 percentage points, P = .002).

Additionally, patients who had not been vaccinated in the prior season saw the most significant improvements in vaccine uptake, with a +13.7 percentage point increase for those receiving cardiovascular benefit communications (P <.001). Investigators also noted this effect was most pronounced in patients with more recent myocardial infarctions (P <.001).

Relevant disclosures for Bhatt include Sanofi and Novo Nordisk.

References:

1. Bhatt AS. Electronic Nudges to Increase Influenza Vaccination among Patients with History of Myocardial Infarction: Insights from 3 Randomized Clinical Trials Enrolling >2 Million Patients. Paper presented at: American Heart Association Scientific Sessions 2024; November 15 - 18; Chicago, Il. Accessed November 16, 2024.
2. American Heart Association. Email reminders improved flu shot rates in Denmark, notably among heart attack survivors. American Heart Association Newsroom. November 11, 2024. Accessed November 17, 2024. https://newsroom.heart.org/news/email-reminders-improved-flu-shot-rates-in-denmark-notably-among-heart-attack-survivors.