Economic Evaluation of a Mobile Diary App versus Paper-based Diary Cards for Patients with Borderline Personality Disorder (Preprint)

BACKGROUND The use of mobile diary applications (apps) in dialectical behaviour therapy (DBT) could entail several positive consequences, such as allowing therapists to follow their patients during treatment. OBJECTIVE The objective of this study was to examine the costs and consequences of using a mobile diary app compared to paper-based diary cards in DBT treatment for patients with borderline personality disorder (BPD) in a psychiatric outpatient facility to develop the current knowledge. METHODS The study was conducted alongside a pragmatic, multicentre randomized controlled trial. Participants were recruited at five Danish psychiatric outpatient facilities and were randomized to register emotions, urges, and skills use in a mobile diary app or on paper-based diary cards. Participants in both groups received DBT delivered by therapists. A cost-consequence analysis with a time horizon of 12 months was undertaken. Consequences included quality-adjusted life years (QALY), depression severity, borderline severity, suicidal behaviour, healthcare use, and treatment compliance. Moreover, advantages and disadvantages of using a mobile diary app were studied. All relevant costs were included. RESULTS In total, 78 participants were included in the analysis. Participants in both groups had a QALY gain, and a decrease in depression severity, borderline severity, and suicidal behaviour. Significant differences were found between the app group and the paper group for both QALY gain (adjusted difference -0.054, SE 0.03) and depression severity (adjusted difference -1.11, SE 1.57). The use of services in the healthcare sector was similar across both time points and groups (difference: psychiatric hospitalization <5 and <5, general practice -1.32, SE 3.68 and 2.02, SE 3.19). An insignificantly higher number of participants in the paper group dropped out before treatment start (P value .07). Of those starting treatment, participants in the app group had an average of 37.1 (SE 27.55) more days of treatment and registered an average of 3.16 (SE 5.10) more skills per week than participants in the paper group. The mobile diary app was considered timesaving as it was expected to be 1 minute faster to complete. Advantages of the app were the opportunity to choose between different methods of registering; comparative ease of use; increased self-insight; and a new type of data collection. Disadvantages were a negative influence on the therapist-patient interaction; worries about performance goals; reduced flexibility in data collection; and implementation issues. The between-group difference in total costs ranged from £78.15-234.44 per participant during the 12-months. CONCLUSIONS A mobile diary app can potentially entail several positive consequences for patients suffering from BPD although at a higher cost than paper-based diary cards. A mobile diary app might contribute with new information on the patients, which is not available from the paper diary. Further research is encouraged, as this is still a new field. CLINICALTRIAL ClinicalTrials.gov NCT03191565 INTERNATIONAL REGISTERED REPORT RR2-