Phillips M, İnce B, Webb H, Dalton B, McCombie C, Irish M, Mercado D, Peachey G, Zenasni Z, Himmerich H, Robinson P, Arcelus J, Byford S, Treasure J, Landau S, Lawrence V, and Schmidt U
Objective: The DAISIES trial, comparing inpatient and stepped-care day patient treatment for adults with severe anorexia nervosa was prematurely terminated in March 2022 due to poor recruitment. This qualitative study seeks to understand the difficulties faced during the trial by investigating stakeholders' views on and experiences of its implementation., Method: Semi-structured interview and focus group transcripts, and trial management and oversight group meeting minutes from May 2020-June 2022 were analysed using thematic analysis. Participants were 47 clinicians and co-investigators involved with the DAISIES trial. The Non-Adoption, Abandonment, Scale-up, Spread, and Sustainability (NASSS) framework was applied to the interpretive themes to classify barriers and facilitators to implementation., Results: Five themes were identified: incompatible participation interests; changing standard practice; concerns around clinical management; systemic capacity and capability issues; and Covid-19 disrupting implementation. Applying the NASSS framework indicated the greatest implementation challenges to arise with the adopters (e.g. patients, clinicians), the organisational systems (e.g. service capacity), and the wider socio-political context (e.g. Covid-19 closing services)., Conclusions: Our findings emphasise the top-down impact of systemic-level research implementation challenges. The impact of the Covid-19 pandemic accentuated pre-existing organisational barriers to trial implementation within intensive eating disorder services, further limiting the capacity for research., (© 2023 The Authors. European Eating Disorders Review published by Eating Disorders Association and John Wiley & Sons Ltd.)