Effects of Message Framing and Time Discounting on Health Communication for Optimum Cardiovascular Disease and Stroke Prevention (EMT-OCSP): a protocol for a pragmatic, multicentre, observer-blinded, 12-month randomised controlled study.

INTRODUCTION Primary prevention of cardiovascular disease (CVD) and stroke often fails due to poor adherence among patients to evidence-based prevention recommendations. The proper formatting of messages portraying CVD and stroke risks and interventional benefits may promote individuals' perception and motivation, adherence to healthy plans and eventual success in achieving risk control. The main objective of this study is to determine whether risk and intervention communication strategies (gain-framed vs loss-framed and long-term vs short-term contexts) and potential interaction thereof have different effects on the optimisation of adherence to clinical preventive management for the endpoint of CVD risk reduction among subjects with at least one CVD risk factor. METHODS AND ANALYSIS This trial is designed as a 2×2 factorial, observer-blinded multicentre randomised controlled study with four parallel groups. Trial participants are aged 45-80 years and have at least one CVD risk factor. Based on sample size calculations for primary outcome, we plan to enrol 15 000 participants. Data collection will occur at baseline, 6 months and 1 year after randomisation. The primary outcomes are changes in the estimated 10-year CVD risk, estimated lifetime CVD risk and estimated CVD-free life expectancy from baseline to the 1-year follow-up. ETHICS AND DISSEMINATION This study received approval from the Ethical Committee of West China Hospital, Sichuan University and will be disseminated via peer-reviewed publications and conference presentations. TRIAL REGISTRATION NUMBER NCT04450888.