Long-term cardiovascular risk in post-cardiac rehabilitation patients after one year follow-up using a smartphone application: 4-year post intervention follow-up of a randomized controlled trial

Abstract Background Adherence to healthy behaviour adapted in cardiac rehabilitation (CR) is challenging for many patients. In 2020, we demonstrated that one year of individualized follow-up using a smartphone-application (app) is effective to promote adherence to healthy behaviour post-CR (1). However, long-term data evaluating the effect of mobile health (mHealth) intervention regarding adherence to healthy behaviour are sparse. Purpose The purpose of the present study was to assess the effects of individualized follow-up with an app for one year in patients post-CR, four-year post intervention. Methods A single-blinded randomized controlled trial lasting for one year with follow-up four-year post-intervention. The intervention group (IG) received follow-up enabled with an app for one year, while the control group (CG) received usual care. After the intervention period, all patients received usual care for the next four years. The primary outcome was difference in peak oxygen uptake (VO2peak). In addition, exercise performance (time to exhaustion at cardiopulmonary exercise test), cardiac events, cholesterol, body weight, quality of life and health status were evaluated. Data were analysed in accordance with the intention-to-treat principle. Linear mixed models for repeated measurements were used to analyse for differences between groups. All tests were two-sided, and p-values ≤0.05 were considered as statistically significant. Results A total of 113 patients completing CR (88 med/25 women, mean age 59±8.7 years, 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 post-CR (Table 1). As previously reported (1) and presented at ESC Preventive Cardiology 2020, there were statistically significant differences between the groups in favour of the IG in VO2peak and exercise performance at the end of the intervention period (one-year post-CR). At four-year post intervention, 102 patients were assessed. There were no statistically significant differences between the groups in any outcomes evaluated (Table 2). In total, 33 patients experienced a new cardiac event post-CR, 12 (5 in the CG and 7 in the IG) during the first year, and 21 (11 in the CG and 10 in the IG) during the four-year post intervention period. Conclusion Individualized follow-up enabled with an app for one year is effective to improve VO2peak, exercise performance and exercise habits in patients post-CR. Despite the positive effects observed one-year post-CR, these benefits have ceased to exist four years post intervention. Results from this study is of significant clinical importance for the future implementation of technology to promote lifelong adherence to healthy behaviour post lifestyle interventions, such as CR.