Background:Patients’ first-hand experiences of faecal microbiota transplantation (FMT) performed in a rheumatological care-setting have yet to be elucidated.Objectives:The objectives were to explore participants’ perceptions of being part of an FMT trial thereby identifying potential trial participation effects and enlightening the patient perspective on the outlook for future FMT trials in rheumatic diseases.Methods:In a qualitative study nested within a double-blind, randomised, placebo-controlled trial (RCT) testing FMT as a potential new anti-rheumatic treatment,¹ semi-structured telephone interviews were conducted following the trial participants’ final 26-week visit. The RCT was conducted at a Danish rheumatology university outpatient clinic with nationwide inclusion. The qualitative study included ten patients with psoriatic arthritis (PsA) who completed the final 26-week trial visit and were unaware of their treatment allocation (one gastroscopic-guided FMT or sham transplantation into the duodenum), see table 1. Qualitative researchers, who did not take part in the RCT, performed the interviews and the primary analysis. The experiences explored related to the conduct of the RCT and changes in the participants’ everyday life. The analysis was carried out using a thematic approach. There was sufficient repetition of ideas in data to conclude data saturation.Table 1.Characteristics of the participants.CharacteristicTotal(n = 10)Female sex, no. (%)7 (70%)Age, yr.53.9 (11.3)Time since diagnosis, yr.^a7.4 (4.2, 12.8)Rheumatoid factor IgM negative, no. (%)10 (100%)Anti-citrullinated peptide antibody negative, no. (%)10 (100%)HLA-B27 negative, no. (%)8 (80%)C-reactive protein, mg/L4.5 (3.6)HAQ-DI^b1.09 (0.40)Swollen joint 66 count7.4 (3.8)Tender joint 68 count22.8 (7.9)SPARCC enthesitis index^cScore ≥1, no. (%)10 (100%)Score in patients with a score ≥18.7 (4.0)Data are mean (SD) or n (%) unless otherwise stated.^a Time since diagnosis of psoriatic arthritis is presented as median and interquartile range (IQR).^b Scores on the Health Assessment Questionnaire Disability Index (HAQ-DI) range from 0 to 3, with higher scores indicating greater disability. ^c Spondyloarthritis Research Consortium of Canada (SPAARC) Enthesitis Index range from 0 to 16, with higher scores indicating more severe disease.Results:Participation in the RCT influenced the patients’ understanding of PsA and induced positive changes in their everyday life. Renewed hopes for the future in addition to a feeling of enhanced care contributed to significant trial participation effects.² We identified several factors related to the RCT that may have promoted these effects (figure 1). FMT was deemed acceptable and safe, and all participants supported more research into the field of microbiota-targeted interventions in rheumatic diseases.Figure 1.Factors related to the RCT that may have promoted trial participation effects.Conclusion:Discrepancies between the clinical and the research setting should be considered when discussing the clinical relevance of the results of the RCT. Overall, patients with PsA who have participated in an RCT testing FMT find the treatment acceptable and safe encouraging more research into the field of microbiota-targeted interventions in rheumatic diseases. Further research into the potential beneficial and adverse effects of FMT in addition to exploring the magnitude and mechanisms behind FMT trial participation effects in the rheumatological setting are highly needed.References:[1]Kragsnaes MS, Kjeldsen J, Horn HC, et al. Efficacy and safety of faecal microbiota transplantation in patients with psoriatic arthritis: protocol for a 6-month, double-blind, randomised, placebo-controlled trial. BMJ open 2018;8:e019231.[2]McCambridge J, Kypri K, Elbourne D. Research participation effects: a skeleton in the methodological cupboard. J Clin Epidemiol 2014;67:845-9.Acknowledgements:The authors thank the patient advisers and all the participants who shared their experiences with us.Disclosure of Interests:Maja Skov Kragsnaes Grant/research support from: Novartis 2017 (unrestricted research grant) to cover 3 months PhD salary in relation to the study., Shaun Theodor Sødergren: None declared, Jens Kjeldsen: None declared, Hans Christian Horn: None declared, Heidi Lausten Munk: None declared, Jens Kristian Pedersen: None declared, Camilla Schufri Klinkby: None declared, Maarten de Wit: None declared, Nanna Gram Ahlmark: None declared, Tine Tjørnhøj-Thomsen: None declared, Torkell Ellingsen Grant/research support from: Novartis 2017 (unrestricted research grant)