A Self-Administered Gamified Mobile Application for Secondary Prevention of Heart Disease in Patients Following a Cardiac Event (MyHeartMate): Process Evaluation from a Randomized Controlled Trial

<i><b>Objective:</b></i> This study reports the process evaluation of a randomized controlled trial of the MyHeartMate app for patients with coronary heart disease (CHD). <i><b>Materials and Methods:</b></i> Data were collected on engagement in the intervention group from the app platform logs and self-reported usage and via interviews for perspectives of usefulness and acceptability. Participants' (<i>n</i> = 194) data logs showed 80.4% entered baseline data. Tracking (≥30 days) occurred for body mass index (23.2%), blood pressure (BP) (21.1%), and exercise (23.7%). Missions completed on ≥4 days were 47.5% for healthy eating and 30.9% for exercise; 50.5% used the word game. One quarter (26.8%) was classified as "engaged" (tracked exercise and/or BP ≥5 times and completed ≥18 missions in the first 30 days). There were no differences between participants who were "engaged" or not in baseline characteristics or 6-month outcomes, although engaged users were more likely to meet 4/5 recommended risk factor guideline levels (30.8% vs. 17.6%, <i>P</i> = 0.03). <i><b>Results:</b></i> Participants perceived tracking, prompts, and rewards as useful for recovery and risk factor-related lifestyle change, and games were enjoyed. Engagement decreased with time. Acceptability was limited when app processes were difficult to understand, not personalized enough and/or the overall game concept was disliked. <i><b>Conclusions:</b></i> Insight into user's perceptions and use of gamified app components is essential to address barriers to uptake and optimize potential health benefits. The target audience for a serious game app for CHD remains uncertain.