Electronic Nudge Letters to Increase Influenza Vaccination Uptake in Younger and Middle-Aged Individuals With Diabetes

Mats C.Højbjerg Lassen, Niklas Dyrby Johansen, Muthiah Vaduganathan, Ankeet S. Bhatt, Daniel Modin, Safia Chatur, Brian L. Claggett, Kira Hyldekær Janstrup, Carsten Schade Larsen, Lykke Larsen, Lothar Wiese, Michael Dalager-Pedersen, Lars Køber, Scott D. Solomon, Pradeesh Sivapalan, Jens Ulrik Stæhr Jensen, Cyril Jean Marie Martel, Tyra Grove Krause, Tor Biering-Sørensen*

*Corresponding author for this work

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Abstract

Background: Despite evidence demonstrating that influenza vaccination is associated with reduced risk of cardiovascular events and all-cause mortality in individuals with diabetes mellitus (DM), vaccine uptake remains suboptimal. Objectives: The purpose of this study was to assess the effectiveness of electronically delivered nudges on influenza vaccine uptake according to the presence of DM status versus other chronic diseases. Methods: NUDGE-FLU-CHRONIC was a nationwide, randomized, pragmatic implementation trial among younger and middle-aged (18-64 years) Danish citizens with chronic disease during the 2023/2024 influenza season. Participants were randomized in a 2.45:1:1:1:1:1:1 ratio to usual care (no electronic letter) or 1 of 6 different electronic nudge letters. The endpoint was receipt of a seasonal influenza vaccine on or before January 1, 2024. Results: Of 299,881 participants, 57,666 (19.2%) had DM (median age: 51.6 years, 43.0% female). During the season, 43.0% of those with DM vs 34.6% of those without DM received the vaccine (P < 0.001). Any electronic letter vs usual care was highly effective in increasing vaccine uptake in participants with DM (45.6% vs 36.5%, difference: +9.1 percentage points [99.29% CI: 7.9-10.3], relative risk ratio: 1.42 [99.29% CI: 1.39-1.44]). However, DM status modified the effect of the interventions such that participants without DM at baseline experienced a greater relative gain than those with DM (37.3% vs 25.9%, difference: +12.3 percentage points [99.29% CI: 11.7-12.8], risk ratio: 1.47 [99.29% CI: 1.45-1.50]; Pinteraction<0.001). Conclusions: Electronic nudge letters effectively boosted vaccine uptake in individuals with DM and in individuals free of DM but with other chronic diseases, but the effect was lower among those with DM. Electronic nudges represent a low-cost and effective strategy to boost influenza vaccination rates in the DM population. (Nationwide Utilization of Danish Government Electronic Letter System for Increasing InFLUenza Vaccine Uptake Among Adults With Chronic Disease; NCT06030739)

Original languageEnglish
Article number101391
JournalJACC: Advances
Volume3
Issue number12 Part 1
Number of pages13
DOIs
Publication statusPublished - 2024

Bibliographical note

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© 2024 The Authors

Keywords

  • behavioral science
  • diabetes
  • implementation
  • influenza
  • nudging
  • randomized controlled trial
  • registry
  • vaccination

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