Long-term follow-up with a smartphone application improves exercise capacity post cardiac rehabilitation: A randomized controlled trial

BACKGROUND: Mobile health interventions, especially smartphone applications (apps), have been proposed as promising interventions for supporting adherence to healthy behaviour in patients post cardiac rehabilitation (CR). The overall aim of the study was to examine the effect of individualized follow-up with an app for one year on peak oxygen uptake (VO(2peak)) in patients completing CR. DESIGN: The study was designed as a single-blinded multicentre randomized controlled trial. METHODS: The intervention group (IG) received individualized follow-up enabled with an app for one year, while the control group (CG) received usual care. The primary outcome was difference in VO(2peak). Secondary outcomes included exercise performance (time to exhaustion, peak incline (%) and peak velocity (km/h)), bodyweight, resting blood pressure, lipid profile, triglycerides, exercise habits, health-related quality of life, health status and self-perceived goal achievement. RESULTS: In total, 113 patients completing CR (73.4% with coronary artery disease, 16.8% after valve surgery and 9.8% with other heart diseases) were randomly allocated to the IG or CG. Intention to treat analyses showed a statistically significant difference in VO(2peak) between the groups at follow-up of 2.2 ml/kg/min, 95% confidence interval 0.9–3.5 (p < 0.001). Statistically significant differences were also observed in exercise performance, exercise habits and in self-perceived goal achievement. CONCLUSIONS: Individualized follow-up for one year with an app significantly improved VO(2peak), exercise performance and exercise habits, as well as self-perceived goal achievement, compared with a CG in patients post-CR. There were no statistically significant differences between the groups at follow-up in the other outcome measures evaluated.