Improving quality of life in cancer patients with an app-based intervention (Mika-App): secondary results from a randomized controlled waitlist-trial in Germany.

Objective: Psychological distress in cancer patients can be reduced through digital support tools, such as the Mika-App. Yet, the effect on various dimensions of quality of life (QoL) remains unclear. In a secondary analysis of a randomized controlled trial (RCT), we aimed to investigate the effect of the Mika-App on physical and mental QoL, and to explore potential moderators such as age, sex, and digital health literacy (DHL). Methods: Patients diagnosed with cancer within the past five years were recruited for this nationwide RCT in Germany. Participants were randomly assigned to either the intervention group (IG, access to the Mika-App), or the wait-list control group (CG, usual care). Online questionnaires were administered at baseline, 2, 6 and 12 weeks. Physical and mental QoL was assessed with the Short-Form Health Survey (SF-8). Linear mixed-effects models were used to test for changes in QoL over time between groups and to examine moderating effects. Analyses were conducted intention-to-treat (ITT) and per-protocol (PP). Results: A total of 218 patients (IG=99, CG=119) were included, with a mean age of 56 years, 61% being female. Patients in the IG demonstrated significant improvements in mental QoL over time compared to the CG (ITT: F(3, 623.46)=3.58, p=0.014; PP: F(3, 360.38)=5.54, p=0.001), with small-to-medium effect sizes between groups at the 6- and 12-week follow-ups (Cohens' d=0.26-0.69). There was no change in physical QoL in both groups (ITT: p=0.90; PP: p=0.88). Age, sex, and DHL did not moderate the interventions' effect on QoL (all p>0.05). Discussion: While physical QoL remained unchanged, mental QoL significantly improved. This reflects the app's content features, mainly targeting self-management skills and psychological distress. The app appears to be equally beneficial across all age groups, for men and women. Since DHL was particularly high in our sample, possibly due to the predominantly online recruitment strategy, results on DHL need to be interpreted with caution. Further research is needed on the role of DHL in the efficacy of digital support tools in the context of routine clinical care. Conclusion: Digital support tools have the potential to improve QoL in patients with cancer. Integrating these tools into clinical care practice might provide valuable support for patients in need by addressing their specific symptoms.