TY - JOUR

T1 - Clinical Outcomes With Electronic Nudges to Increase Influenza Vaccination

AU - Johansen, Niklas Dyrby

AU - Vaduganathan, Muthiah

AU - Bhatt, Ankeet S.

AU - Lee, Simin Gharib

AU - Modin, Daniel

AU - Claggett, Brian L.

AU - Dueger, Erica L.

AU - Samson, Sandrine

AU - Loiacono, Matthew M.

AU - Harris, Rebecca C.

AU - Køber, Lars

AU - Solomon, Scott D.

AU - Sivapalan, Pradeesh

AU - Jensen, Jens Ulrik Stæhr

AU - Martel, Cyril Jean Marie

AU - Krause, Tyra Grove

AU - Biering-Sørensen, Tor

N1 - Publisher Copyright: © 2024 American College of Physicians. All rights reserved.

PY - 2024

Y1 - 2024

N2 - Background: In the NUDGE-FLU (Nationwide Utilization of Danish Government Electronic letter system for increasing inFLUenza vaccine uptake) trial, electronic letters incorporating cardiovascular (CV) gain-framing and repeated messaging increased influenza vaccination by approximately 1 percentage point. Objective: To evaluate the effects of the successful nudging interventions on downstream clinical outcomes. Design: Prespecified exploratory analysis of a nationwide randomized implementation trial. (ClinicalTrials. gov: NCT05542004) Setting: The 2022 to 2023 influenza season. Participants: 964 870 Danish citizens aged 65 years or older. Intervention: Usual care or 9 different electronically delivered behavioral nudging letters. Measurements: Cardiovascular, respiratory, and other clinical end points during follow-up from intervention delivery (16 September 2022) through 31 May 2023. Results: The analysis set included 691 820 participants. Hospitalization for pneumonia or influenza occurred in 3354 of 346 327 (1.0%) participants in the usual care group, 396 of 38 586 (1.0%) in the CV gain-framing group (hazard ratio [HR], 1.06 [95% CI, 0.95 to 1.18]; versus usual care), and 403 of 38 231 (1.1%) in the repeated letter group (HR, 1.09 [CI, 0.98 to 1.21]; versus usual care). In the usual care group, 44 682 (12.9%) participants were hospitalized for any cause, compared with 5002 (13.0%) in the CV gain-framing group (HR, 1.00 [CI, 0.97 to 1.03]; versus usual care) and 4965 (13.0%) in the repeated letter group (HR, 1.01 [CI, 0.98 to 1.04]; versus usual care). A total of 6341 (1.8%) participants died in the usual care group, compared with 721 (1.9%) in the CV gain-framing group (HR, 1.02 [CI, 0.94 to 1.10]; versus usual care) and 646 (1.7%) in the repeated letter group (HR, 0.92 [CI, 0.85 to 1.00]; versus usual care). Limitation: Prespecified but exploratory analysis, potential misclassification of events in routinely collected registry data, and results may not be generalizable to other health systems or countries with other racial compositions and/or cultural or societal norms. Conclusion: In a prespecified exploratory analysis, modest increases in influenza vaccination rates seen with electronic nudges did not translate into observable improvements in clinical outcomes. Seasonal influenza vaccination should remain strongly recommended.

AB - Background: In the NUDGE-FLU (Nationwide Utilization of Danish Government Electronic letter system for increasing inFLUenza vaccine uptake) trial, electronic letters incorporating cardiovascular (CV) gain-framing and repeated messaging increased influenza vaccination by approximately 1 percentage point. Objective: To evaluate the effects of the successful nudging interventions on downstream clinical outcomes. Design: Prespecified exploratory analysis of a nationwide randomized implementation trial. (ClinicalTrials. gov: NCT05542004) Setting: The 2022 to 2023 influenza season. Participants: 964 870 Danish citizens aged 65 years or older. Intervention: Usual care or 9 different electronically delivered behavioral nudging letters. Measurements: Cardiovascular, respiratory, and other clinical end points during follow-up from intervention delivery (16 September 2022) through 31 May 2023. Results: The analysis set included 691 820 participants. Hospitalization for pneumonia or influenza occurred in 3354 of 346 327 (1.0%) participants in the usual care group, 396 of 38 586 (1.0%) in the CV gain-framing group (hazard ratio [HR], 1.06 [95% CI, 0.95 to 1.18]; versus usual care), and 403 of 38 231 (1.1%) in the repeated letter group (HR, 1.09 [CI, 0.98 to 1.21]; versus usual care). In the usual care group, 44 682 (12.9%) participants were hospitalized for any cause, compared with 5002 (13.0%) in the CV gain-framing group (HR, 1.00 [CI, 0.97 to 1.03]; versus usual care) and 4965 (13.0%) in the repeated letter group (HR, 1.01 [CI, 0.98 to 1.04]; versus usual care). A total of 6341 (1.8%) participants died in the usual care group, compared with 721 (1.9%) in the CV gain-framing group (HR, 1.02 [CI, 0.94 to 1.10]; versus usual care) and 646 (1.7%) in the repeated letter group (HR, 0.92 [CI, 0.85 to 1.00]; versus usual care). Limitation: Prespecified but exploratory analysis, potential misclassification of events in routinely collected registry data, and results may not be generalizable to other health systems or countries with other racial compositions and/or cultural or societal norms. Conclusion: In a prespecified exploratory analysis, modest increases in influenza vaccination rates seen with electronic nudges did not translate into observable improvements in clinical outcomes. Seasonal influenza vaccination should remain strongly recommended.

KW - A Prespecified Analysis of a Nationwide

KW - Pragmatic

KW - Randomized Implementation Trial

KW - Registry-Based

U2 - 10.7326/M23-2638

DO - 10.7326/M23-2638

M3 - Journal article

C2 - 38498876

AN - SCOPUS:85190900279

VL - 177

SP - 476

EP - 483

JO - Annals of Internal Medicine

JF - Annals of Internal Medicine

SN - 0003-4819

IS - 4

ER -