Cost-utility and cost-effectiveness of SELFIE, a transdiagnostic ecological momentary intervention for improving self-esteem in youth aged 12-26 exposed to childhood adversity: findings from a multi-centre randomized controlled trial

Young people benefited from SELFIE, a novel transdiagnostic blended Ecological Momentary Intervention (EMI) for improving self-esteem in youth with prior exposure to childhood adversity. However, health-economic evaluations are lacking in the field of EMIs for young people and largely for interventions among youth exposed to childhood adversity. To evaluate cost-effectiveness and cost-utility of SELFIE compared to care as usual (CAU), from a societal and healthcare perspective, following the CHEERS-guideline.Participants aged 12-26 years with low self-esteem and prior exposure to childhood adversity were randomly allocated to receive CAU (control condition) or CAU+SELFIE (experimental condition). The Trimbos/iMTA Questionnaire for Costs Associated with Psychiatric Illness (TiC-P), the Rosenberg Self-Esteem Scale (RSES; effect) and EQ-5D-5L (QALYs; utility) were assessed at baseline, postintervention and at 6-, 18- and 24-month follow-up. For the main analysis, incremental planes and acceptability curves were generated. Sensitivity and subgroup analyses were performed. For cost-utility, willingness-to-pay (WTP) levels of €20,000 and €50,000/QALY were used.The ICER presented a cost of €1,239 per improved point of self-esteem on the RSES, and the ICUR presented a cost of €53,983 per QALY gained. From a societal perspective, the probability that the SELFIE intervention would be cost-effective in terms of cost-utility was 26% at a WTP of €20,000/QALY and 49% at €50,000/QALY. From a healthcare-only perspective, the probability of cost-effectiveness was 56% at a WTP of €20,000/QALY and 77% at €50,000/QALY. Each improvement in QALYs costed €15,667.The SELFIE intervention is cost-effective compared to CAU in terms of effect, and for cost-utility for all costs excluding work productivity. Measuring educational productivity is advised for future health-economic evaluations among young people to more completely evaluate the societal perspective. The innovative field of blended EMIs yields encouraging first results for routine public mental health care, urging more (currently scarce) cost-effectiveness research.