Participants and setting
Youth with CMC were recruited between April and July 2022 upon presentation at the University Children’s Hospital Duesseldorf, Germany. Inclusion criteria were (1) age between 12 and 16 years, (2) having a CMC (defined as having a disease for over a year, mandatory long-term medical care or a significant impairment of daily life routine), (3) sufficient knowledge of German or English for app usage and coaching participation, (4) sufficient physical and mental condition for study participation (Lansky score ≥ 80 [26]), (5) access to an Internet-enabled smart phone, (6) a signed informed consent form by both parents and participants (7) no prior history of psychiatric or psychological treatment in the last three months or longer than three months).
Based on the approach of Whitehead et al., at least 25 participants per group were planned for a subsequent main trial designed with 90% power and an effect size of 0.1 ≤ δ <0.3 (Cohen’s d).[27] The minimum sample size therefore was n=50.
Outcome measures
Primary endpoint was the feasibility of the REThink + Coaching intervention.
Based on previous studies[21, 28], the following feasibility criteria were defined:
- 70% of youth who meet the inclusion criteria can be recruited,
- 85% of participants complete all levels of the REThink app,
- 70% of participants in the REThink + Coaching group participate in both group sessions.
Based on the principles of Thabane et al.[29], the following secondary outcomes were evaluated:
- What is the youths’ adherence (rejection rate, loss to follow-up rate)?
- What are reasons for participation/non-participation? What do youth like and dislike about the app and coaching?
- Which population groups does the study reach?
- Considering the overall population of youth with CMC, should one offer a low-threshold resilience app game or a combined training intervention with in-depth coaching?
Additionally, resilience and automatic negative thoughts were examined at baseline, post-intervention, and in two-month follow-up.
Sociodemographic questionnaire for youth and parents
The sociodemographic questionnaire comprised information on age, gender, nationality, chronic disease, educational attainment, socioeconomic status, media and app use. Subjective socioeconomic status was assessed as described by Lampert et al. in the KiGGS Wave 2 study.[30]
Coaching and app game evaluation questionnaire
Usefulness and satisfaction were assessed on a five-point Likert scale for app and coaching. Based on the questionnaire by David et al. usage difficulties, target age group, liked or disliked aspects, preferred app level, subjective resilience improvement, recommendation for friends and preference of in-person or online meetings were assessed for app and coaching if applicable.[31]
Resilience scale 13 (RS-13)
The 13-item Resilience Scale (RS-13) is the short form of the Resilience scale (RS-25) by Wagnild et al. and measures resilience as a person’s positive characteristic of individual adaptability.[32] Participants are asked to indicate their agreement with certain phrases on a seven-point Likert scale. The RS-13 has high internal reliability (Cronbach’s α = 0.90), the retest-reliability is good (0.62).[32] A sum score from 13 to 66 points is considered as low resilience, 67 to 72 points as moderate and 73 to 91 points as high resilience.[32]
Children’s automatic thoughts scale (CATS)
The Children’s Automatic Thoughts Scale is a 40-item questionnaire that assesses negative self-statements in children and adolescents.[33] It comprises four subscales: physical threat, social threat, personal failure, hostility. Participants rate to what extent they had the respective thought over the past week on a five-point-Likert scale. The CATS showed high internal consistency (Cronbach’s α = 0.95), the retest-reliability was good (0.76).[33] A sum score of ≥ 70 points is considered as clinical cut-off point for internalizing or externalizing problems (anxiety, depression or behavior disorder).
Study Design
In a two-arm randomized controlled trial (RCT) participants were randomly assigned to either the REThink + Coaching or only REThink app group (stratified by age and gender). If participation was refused, youths and parents were asked to state their reasons for rejection anonymously. Eligible youths were identified through search of the specialty clinics’ patient registries and the emergency room and inpatient calendars.
At baseline youth participants completed the RS-13 and CATS pre-, post-intervention (defined as seven weeks after baseline) and in a two-month follow up. At baseline, youth and parents further completed a sociodemographic questionnaire. Post-intervention youth also received an evaluation questionnaire and participated in a short semi-structured interview on app and coaching evaluation. Participants were reminded a maximum of three times via E-mail to complete the questionnaires. The participants received a total of 20 Euro in gift vouchers as incentives. Detailed information on study procedures and data collection can be found in the Supplementary Information.
Intervention
REThink app
The REThink app was developed by the Babes-Bolyai University, Romania, to promote emotional resilience in youth. Based on Rational Emotive Behavioral Therapy, the REThink app focuses on teaching youth coping strategies for dysfunctional negative emotions through seven mini-games.[31] Detailed information on app content can be found in the Supplementary Information.
For this study an English audio version with German subtitles was developed. The player’s date of play and level played were collected. Participants were instructed to complete at least one level every week for seven weeks. If the corresponding module of the week had not been played, participants were reminded via E-mail (once per week).
Cognitive behavioral therapy based online-coaching
The coaching manual was jointly developed by the study team and pediatric psychologists. The coaching content was based on cognitive behavioral therapy and coordinated with the app topics. The coaching sessions were led by experienced clinicians and psychology students with a bachelor’s degree. Detailed information on manual development can be found in the Supplementary Information.
REThink + Coaching participants were instructed to play the REThink app and received two additional group coaching sessions in groups of 6 to 10 participants (duration 60 to 90 minutes). They could choose between online or in-person sessions at the children’s clinic, however, no in-person coachings were held due to low demand. Participants were reminded to participate via E-mail or phone one day before their sessions.
Statistical Analysis
The analysis focused on a quantitative evaluation of feasibility. However, data on the necessary parameters for use in a larger future RCT were collected. Data from all randomized participants were analyzed (intention-to-treat-collective). First, a descriptive analysis of the sociodemographic data, RS-13/CATS-scores at baseline and evaluation forms was performed. Socioeconomic status quintiles were calculated according to Lampert et al.[30]. Chi-square tests/t-tests were used to determine if there were significant differences by group at baseline (for frequencies <5 fisher’s exact test was used). For the analysis of differences by group between baseline, post-intervention and follow-up Wilcoxon signed-rank tests were used as some differences were not normally distributed. Thirdly, an exploratory analysis using ANOVA calculations was performed to test for group x time interaction effects. The effect size for mean differences between groups was estimated according to Morris.[34, 35] Uni- and multivariate logistic regressions were computed for coaching and app adherence with age, disease, socioeconomic status and group membership as explanatory variables. Analyses were performed in SPSS version 28.0. and R version 4.2.1, figures were created using Adobe Illustrator CC 2019.[36-38] The study findings are reported according to the CONSORT Statement (see Supplementary Information for CONSORT checklist).