Estimating the Economic Value of Supported Online Parent-Led Cognitive Behavioral Therapy to Prevent Child Anxiety Problems: Economic Evaluation of the MYCATS Cluster Randomized Controlled Trial

BACKGROUND: Childhood anxiety disorders are common and lead to substantial negative long-term outcomes in various life domains. Although digital interventions for preventing childhood anxiety problems have been increasingly used in the recent decade, there is limited evidence documenting their cost-effectiveness (CE). OBJECTIVE: This study aimed to evaluate the CE of a parent-led online cognitive behavioral therapy with therapist support (OSI+TS) alongside usual school practice (USP), compared to USP alone for children aged 4-7 years at risk of anxiety disorders identified through universal school screening. METHODS: The economic evaluation was conducted alongside the MYCATS trial (N=865), a parallel group, superiority cluster randomized trial across 95 primary or infant schools in England. Schools were randomized (1:1) to OSI+TS or USP, stratified by school-level deprivation. The primary analyses, at 12 months after randomization, considered child quality-adjusted life years (QALYs) as the health economic outcome, using both the UK adult and the Australia adolescent value sets, and costs were from the National Health Service and Personal Social Services perspective. Incremental cost-effectiveness ratios (ICERs) were compared to the UK National Institute for Health and Care Excellence (NICE) recommended threshold of £20,000-£30,000 (£1=US $1.35 as of September 10, 2026) per QALY gained, as per predefined Health Economics Analysis Plan. Sensitivity analyses included a societal perspective and the application of the new NICE cost-effectiveness threshold. RESULTS: Children receiving OSI+TS gained 0.021 (95% CI 0.010-0.033; P<.001) and 0.043 (95% CI 0.021-0.064; P<.001) QALYs, respectively, for United Kingdom and Australia value sets, with an additional cost of £244.16 compared to school usual practice only, resulting in ICERs of £11,462.47 and £5,700.98, respectively. At the £20,000 threshold, OSI+TS had an 88.2% or 99.3% chance of being cost-effective. CONCLUSIONS: OSI+TS is cost-effective compared to usual school provision, supporting its future implementation for children at risk of anxiety problems.