Electronic nudges to increase influenza vaccination uptake in Denmark: a nationwide, pragmatic, registry-based, randomised implementation trial

Johansen, Niklas Dyrby; Vaduganathan, Muthiah; Bhatt, Ankeet S.; Lee, Simin Gharib; Modin, Daniel; Claggett, Brian; Dueger, Erica; Samson, Sandrine; Loiacono, Matthew M.; Køber, Lars; Solomon, Scott D.; Sivapalan, Pradeesh; Jensen, Jens Ulrik Stæhr; Martel, Cyril Jean‐Marie; Valentiner‐Branth, Palle; Krause, Tyra Grove

doi:10.1016/s0140-6736(23)00349-5

Cited by 35 publications

(27 citation statements)

References 22 publications

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“…NUDGE-FLU demonstrated an accentuated effect of the CV gain-framed letter in patients who were not vaccinated in the prior season compared to those that had received vaccination. 9 As highlighted in the present report and mirrored in estimates in other countries, vaccination uptake was considerably lower in patients aged <65 years compared to those ≥65 years. Therefore, this younger population may represent a more 'nudgeable' target subgroup and is an important area for similar future study.…”

Section: Egosupporting

confidence: 81%

Give a nudge a shot: NUDGE‐FLU bridging the cardiovascular quality chasm

Chatur

2023

European J of Heart Fail

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Section: Egosupporting

confidence: 81%

Give a nudge a shot: NUDGE‐FLU bridging the cardiovascular quality chasm

Chatur

2023

European J of Heart Fail

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“…Nevertheless, the NUDGE-FLU trial is the first study to demonstrate nationwide feasibility of using a governmental electronic letter system to conduct a randomized implementation trial with effective data collection through nationwide registers. 17 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.…”

Section: Discussionmentioning

confidence: 97%

“…The rationale, design, and results of the NUDGE-FLU trial have been reported previously. 17 In brief, NUDGE-FLU was a randomized, pragmatic, nationwide, registry-based trial conducted during the 2022 to 2023 influenza season designed to evaluate the effect of digital behavioral nudges delivered through the Danish governmental electronic letter system on influenza vaccine uptake in persons 65 years of age or older. The trial was sponsored by the Center for Translational Cardiology and Pragmatic Randomized Trials at Copenhagen University Hospital – Herlev and Gentofte, Denmark, and funding was provided by Sanofi.…”

Section: Methodsmentioning

confidence: 99%

“…The NUDGE-FLU trial (Nationwide Utilization of Danish Government Electronic Letter System for Increasing Influenza Vaccine Uptake) was conducted to test the hypothesis that behavioral nudges delivered through the Danish mandatory governmental electronic letter system could increase influenza vaccination rates in persons 65 years of age and older. The trial found that 2 strategies significantly increased influenza vaccination rates compared with usual care 17 : a letter emphasizing the potential cardiovascular benefits of influenza vaccination, and a repeated letter strategy with a reminder follow-up letter 14 days later. This in-depth, prespecified analysis aimed to provide further detail on the effect of digital behavioral nudges tested in NUDGE-FLU on influenza vaccine uptake based on the presence or absence of CVD and across major CVD subgroups including heart failure, ischemic heart disease, cerebrovascular disease, and atrial fibrillation.…”

mentioning

confidence: 99%

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Effect of Electronic Nudges on Influenza Vaccination Rate in Older Adults With Cardiovascular Disease: Prespecified Analysis of the NUDGE-FLU Trial

et al. 2023

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Background: Influenza vaccines have been demonstrated to effectively reduce the incidence of influenza infection and potentially associated risks of cardiovascular events in patients with cardiovascular disease (CVD). Despite strong guideline and public health endorsements, global influenza vaccination rates in patients with CVD are highly variable. This prespecified analysis of NUDGE-FLU (Nationwide Utilization of Danish Government Electronic Letter System for Increasing InFLUenza Vaccine Uptake) examined the effect of digital behavioral nudges on influenza vaccine uptake based on the presence of cardiovascular disease. Methods: NUDGE-FLU was a randomized, pragmatic, nationwide, register-based trial including Danish citizens aged 65 years or older 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 9 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 cardiovascular disease and across cardiovascular 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 vs 79.2% of participants without CVD received influenza vaccination (p<0.001). Compared with usual care, a letter emphasizing the potential cardiovascular benefits of influenza vaccination increased vaccination rates; this effect was consistent in participants with CVD (absolute difference +0.60 percentage points, 99.55% 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: Electronic letter interventions emphasizing the potential cardiovascular 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 and across cardiovascular subgroups. Electronic nudges may improve influenza vaccine uptake in individuals with CVD.

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“…Our experience with DisCoVeRy also showed high rates of participant refusal due to the control arm. In another setting, the NUDGE-FLU trial recently evaluated 9 different electronic letters to encourage in uenza vaccine uptake in the general population (19), using a parallel-arm design, and could have similarly bene tted from multiple interventions per subject ; only 2 out of 9 arms showed a (small) effect, and the planned instrumental variable analysis could have bene tted from more interventions given to each subject (and so would the subjects themselves). Future similar prevention trials could bene t from distributive randomization.…”

Section: Discussionmentioning

confidence: 99%

Distributive trials : a novel design to screen or evaluate multiple simultaneous interventions in clinical trials

Haviari

Mentré

2023

Preprint

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Background: In some medical indications, numerous interventions have a weak presumption of efficacy, but a good track record or presumption of safety. This makes it feasible to evaluate them simultaneously. Here we introduce a modified factorial trial design that randomly allocates a pre-specified number of interventions to each participant, and statistically tests each intervention. We compare it to factorial trials, parallel-arm trials and multiple head-to-head trials, and derive some good practices for its design and analysis. Methods: We simulated various scenarios involving 4 to 20 candidate interventions among which 2 to 8 could be simultaneously allocated. A binary outcome was assumed. One or two interventions were assumed effective, with various interactions (positive, negative, none). Efficient combinatorics algorithms were created. Sample sizes and power were obtained by simulations in which the statistical test was either a difference in proportions or a logistic regression Wald test with or without interaction terms for adjustment, with a Bonferroni multiplicity-adjusted alpha risk in both cases. All code is provided without the need for compiling. Results: Distributive trials reduce sample sizes 2- to 7-fold compared to parallel arm trials, and increase them 1- to 2-fold compared to factorial trials, mostly when fewer allocations than for the factorial design are possible. An unexpectedly effective intervention causes small decreases in power (<10%) if its effect is additive, but large decreases (possibly down to 0) if not, as for factorial designs. These large decreases are prevented by using interaction terms to adjust the analysis, but these additional estimands have a sample size cost and are better pre-specified. The issue can also be managed by adding a true control arm without any intervention. Conclusion: Distributive randomization is a viable design for mass parallel evaluation of interventions in constrained trial populations. It should be introduced first in clinical settings where many undercharacterized interventions are potentially available, such as disease prevention strategies, digital behavioral interventions, dietary supplements for chronic conditions, or emerging diseases. Pre-trial simulations are recommended, for which tools are provided.

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Electronic nudges to increase influenza vaccination uptake in Denmark: a nationwide, pragmatic, registry-based, randomised implementation trial

Cited by 35 publications

References 22 publications

Give a nudge a shot: NUDGE‐FLU bridging the cardiovascular quality chasm

Give a nudge a shot: NUDGE‐FLU bridging the cardiovascular quality chasm

Effect of Electronic Nudges on Influenza Vaccination Rate in Older Adults With Cardiovascular Disease: Prespecified Analysis of the NUDGE-FLU Trial

Distributive trials : a novel design to screen or evaluate multiple simultaneous interventions in clinical trials

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