ABSTRACT NUMBER: ESOC2026A1736 BEHAVIORAL INSIGHTS FOR PUBLIC HEALTH ENGAGEMENT: A CLUSTER-RANDOMIZED STUDY ON PARENTAL REGISTRATION IN FAST HEROES

Abstract Background and aims FAST Heroes is an international, school-based stroke education programme that improves family stroke preparedness through child-mediated learning. Despite strong evidence of educational and public-health impact, parental engagement with the programme’s digital platform remains low, limiting reinforcement and sustained participation. This study aimed to identify behaviorally informed communication strategies that increase parental online registration. Methods We conducted a prospective, four-arm cluster-controlled trial in 37 kindergartens (n = 872 pupils) that had previously implemented FAST Heroes without parental log-ins. Schools were assigned to one of four strategies: printed letter; e-mail letter with direct registration link; e-mail plus weekly teacher feedback on class-level registrations; or e-mail plus teacher feedback and automated chatbot reminders. The primary outcome was parental registration within eight weeks. Differences across conditions were assessed using chi-square tests, risk ratios and generalized estimating equation logistic regression to account for clustering. Results Parental registration differed significantly by communication strategy (χ2(3) = 27.12, P < 0.001). The highest uptake occurred in the e-mail plus teacher feedback condition (24.1%), followed by stand-alone e-mail (20.0%), printed letter (11.6%) and chatbot-enhanced prompting (7.6%). Compared with printed letters, e-mail plus teacher feedback more than doubled registration likelihood (RR = 2.07, 95% CI: 1.39–3.09). Urban schools showed higher overall engagement, while rural schools performed better in the stand-alone e-mail condition. Class size was not associated with registration. Conclusions Low-friction digital prompts combined with trusted teacher-mediated feedback substantially improve parental engagement in school-based public-health platforms. Messenger credibility and contextual tailoring are key drivers of digital uptake. Conflict of interest This project has received funding from Boehringer Ingelheim (Grant number 695751, 2023).