OBJECTIVE: Evaluate cost, effectiveness and cost-effectiveness of cognitive behavioural therapy for sleep and fatigue (CBT-SF) vs health education (HE) and of CBT-SF vs treatment as usual (TAU) for sleep disturbance and fatigue in acquired brain injury. DESIGN: Economic evaluation from Australian health system and societal perspectives based on data from a June 2017 to October 2023 randomized controlled trial. SUBJECTS: Community-dwelling Australian adults with sleep disturbance and fatigue following acquired brain injury (n = 126). METHODS: Incremental health system costs based on cost of delivery and health service utilization since last follow-up. Incremental effectiveness based on participant-reported sleep quality, fatigue, and quality of life at each timepoint. Productivity gains/losses based on a 1-week activity diary at each timepoint. RESULTS: Reductions in health service utilization from CBT-SF (-A 77, 95% CI: -A ,232, A ,678) offset higher delivery costs (A 33, 95% CI: A 09, A 56) relative to HE, with improvements in quality of life at 2 months post-treatment (0.02, 95% CI: -0.01, 0.05) and an additional 3.37 quality-adjusted life days per participant (95% CI: -4.18, 10.92). CBT-SF dominates HE (less costly and more effective) and is likely more cost-effective than HE (66-76%). CBT-SF is cost-effective relative to TAU under realistic assumptions. CONCLUSIONS: CBT-SF after acquired brain injury improved clinical and economic outcomes and was more likely to be cost-effective than HE. Further research is required to precisely estimate the cost-effectiveness of CBT-SF vs TAU and to demonstrate generalizability to routine practice and other settings. ANZCTR Trial registration numbers: 1261700087830
12617000879369.