TY - JOUR

T1 - Effect of Electronic Nudges on Influenza Vaccination Rate in Older Adults with Cardiovascular Disease

T2 - Prespecified Analysis of the NUDGE-FLU Trial

AU - Modin, Daniel

AU - Johansen, Niklas Dyrby

AU - Vaduganathan, Muthiah

AU - Bhatt, Ankeet S.

AU - Lee, Simin Gharib

AU - Claggett, Brian L.

AU - Dueger, Erica L.

AU - Samson, Sandrine I.

AU - Loiacono, Matthew M.

AU - Køber, Lars

AU - Solomon, Scott D.

AU - Sivapalan, Pradeesh

AU - Jensen, Jens Ulrik Stæhr

AU - Jean-Marie Martel, Cyril

AU - Valentiner-Branth, Palle

AU - Krause, Tyra Grove

AU - Biering-Sørensen, Tor

N1 - Publisher Copyright: © 2023 Lippincott Williams and Wilkins. All rights reserved.

PY - 2023

Y1 - 2023

N2 - 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 CVD. Methods: NUDGE-FLU was a randomized, pragmatic, nationwide, register-based trial that included Danish citizens 65 years of age or older during the 2022 to 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 end point 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 cardiovascular subgroups that included 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 an 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, 0.27-1.70; 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 7 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. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT05542004.

AB - 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 CVD. Methods: NUDGE-FLU was a randomized, pragmatic, nationwide, register-based trial that included Danish citizens 65 years of age or older during the 2022 to 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 end point 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 cardiovascular subgroups that included 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 an 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, 0.27-1.70; 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 7 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. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT05542004.

KW - behavioral nudge

KW - cardiovascular disease

KW - heart failure

KW - implementation trial

KW - influenza vaccination

KW - influenza vaccine uptake

KW - ischemic heart disease

KW - myocardial infarction

UR - http://www.scopus.com/inward/record.url?scp=85157962939&partnerID=8YFLogxK

U2 - 10.1161/CIRCULATIONAHA.123.064270

DO - 10.1161/CIRCULATIONAHA.123.064270

M3 - Journal article

C2 - 36871213

AN - SCOPUS:85157962939

VL - 147

SP - 1345

EP - 1354

JO - Circulation

JF - Circulation

SN - 0009-7322

IS - 18

ER -