Protocol for a bandit-based response adaptive trial to evaluate the effectiveness of brief self-guided digital interventions for reducing psychological distress in university students: the Vibe Up study.

INTRODUCTION: Meta-analytical evidence confirms a range of interventions, including mindfulness, physical activity and sleep hygiene, can reduce psychological distress in university students. However, it is unclear which intervention is most effective. Artificial intelligence (AI)-driven adaptive trials may be an efficient method to determine what works best and for whom. The primary purpose of the study is to rank the effectiveness of mindfulness, physical activity, sleep hygiene and an active control on reducing distress, using a multiarm contextual bandit-based AI-adaptive trial method. Furthermore, the study will explore which interventions have the largest effect for students with different levels of baseline distress severity. METHODS AND ANALYSIS: The Vibe Up study is a pragmatically oriented, decentralised AI-adaptive group sequential randomised controlled trial comparing the effectiveness of one of three brief, 2-week digital self-guided interventions (mindfulness, physical activity or sleep hygiene) or active control (ecological momentary assessment) in reducing self-reported psychological distress in Australian university students. The adaptive trial methodology involves up to 12 sequential mini-trials that allow for the optimisation of allocation ratios. The primary outcome is change in psychological distress (Depression, Anxiety and Stress Scale, 21-item version, DASS-21 total score) from preintervention to postintervention. Secondary outcomes include change in physical activity, sleep quality and mindfulness from preintervention to postintervention. Planned contrasts will compare the four groups (ie, the three intervention and control) using self-reported psychological distress at prespecified time points for interim analyses. The study aims to determine the best performing intervention, as well as ranking of other interventions. ETHICS AND DISSEMINATION: Ethical approval was sought and obtained from the UNSW Sydney Human Research Ethics Committee (HREC A, HC200466). A trial protocol adhering to the requirements of the Guideline for Good Clinical Practice was prepared for and approved by the Sponsor, UNSW Sydney (Protocol number: HC200466_CTP). TRIAL REGISTRATION NUMBER: ACTRN12621001223820.

The cost-effectiveness of mandatory folic acid fortification in Australia.

The Australian government recently introduced mandatory folic acid fortification of bread to reduce the incidence of neural tube defects (NTDs). The economic evaluation of this policy contained a number of limitations. This study aimed to address the limitations and to reconsider the findings. Cost-effectiveness analysis was used to assess the cost and benefits of mandatory versus voluntary folic acid fortification. Outcomes measures were quality-adjusted life-years (QALYs), life-years gained (LYG), avoided NTD cases, and additional severe neuropathy cases. Costs considered included industry costs and regulatory costs to the government. It was estimated that mandatory fortification would prevent 31 NTDs, whereas an additional 14 cases of severe neuropathy would be incurred. Overall, 539 LYG and 503 QALYs would be gained per year of mandatory compared with voluntary fortification. Mandatory fortification was cost-effective at A$10,723 per LYG and at A$11,485 per QALY. Probabilistic sensitivity analysis showed that at A$60,000 and A$151,000 per QALY, the probability that mandatory fortification was the most cost-effective strategy was 79% and 85%, respectively. Threshold analysis of loss of consumer choice indicated that with a compensation value above A$1.21 [assuming a willingness to pay (WTP) threshold of A$60,000 per QALY] or A$3.19 (assuming a WTP threshold of A$151,000 per statistical life-year) per capita per year mandatory fortification would not be cost-effective. Mandatory fortification was found to be cost-effective; however, inclusion of the loss of consumer choice can change this result. Even with mandatory fortification, mean folate intake will remain below the recommended NTD preventive level.