Assessing the cost-effectiveness of two psychoeducational interventions for people with cancer and their caregivers: An economic evaluation of the multi-country DIAdIC trial

BACKGROUND: Cancer is among the largest drivers of morbidity and mortality worldwide, causing physical, psychological and emotional strain for both patients and caregivers. AIM: We estimated the cost-effectiveness of two dyadic psychoeducational interventions (FOCUS+ and iFOCUS) compared to usual care for people with advanced cancer and their primary family caregiver. METHODS: This was an economic evaluation within a clinical trial. Patient-caregiver dyads were recruited in Belgium, Denmark, Ireland, Italy, Netherlands and the UK from 2021 to 2023. We estimated costs by combining questionnaire responses with unit costs in euros (€) for 2022 and calculated outcomes as quality-adjusted life years (QALYs). Primary endpoint was 12 weeks, with secondary analysis at 24 weeks (trial exit). RESULTS: We recruited 431 dyads (140 FOCUS+, 148 iFOCUS, 143 usual care), of whom 281 (65%) participated to trial end. In primary analysis, estimated treatment effect of FOCUS+ versus usual care on total costs was +€253 (95% CI: -1440 to +3466), and estimated effect on QALYs was +0.010 (-0.02 to +0.04). For iFOCUS compared to usual care, the estimated effects were -€178 (-3047 to +2059) and - 0.001 (-0.04 to +0.04). Estimated incremental cost-effectiveness compared to usual care was highly uncertain in primary analysis, and in sensitivity analyses to timeframe and perspective. CONCLUSION: Two dyadic, psychoeducational interventions for people with advanced cancer and their caregivers were not found to have a significant effect on costs, QALYs or cost-effectiveness compared to usual care. Multiple additional lessons for future trials in serious illness have been identified. TRIAL REGISTRATION: Registration on ClinicalTrials.gov on 12/11/2020, identifier NCT04626349.