AB1643-PARE ASSESSMENT OF PSORIASIS PATIENTS’ PREFERENCES FOR INTERVENTIONS TO PREVENT PSORIATIC ARTHRITIS USING A PROBABILISTIC THRESHOLD TECHNIQUE
Authors: S. Groothuizen, J. W. Bolt, J. Veldwijk, L. C. Coates, M. Falahee, O. Fitzgerald, S. R. Pennington, L. G. M. Van Baarsen, M. G. H. Van de Sande
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> About 20% of psoriasis (PsO) patients develop psoriatic arthritis (PsA) [1]. Several risk factors have been identified and current research projects are aiming to quantify individual risk of developing PsA for PsO patients. There has been a lot of research interest into the potential for intervening to reduce the risk of PsA in people at-risk. However, prior to designing such studies, it is crucial to examine the patient perspective considering the acceptability of interventions with different levels of arthritis risk and different side effects. <h3>Objectives:</h3> We aimed to investigate: a) the minimally accepted level of risk reduction for PsA development that would be needed from the perspective of PsO patients to consider preventive interventions; and b) to explore the maximal acceptable risk of side effects for a hypothetical preventive intervention. <h3>Methods:</h3> Adult PsO patients without PsA in the United Kingdom and the Netherlands were recruited via national PsO patient charities to take part in an online survey. Participants were randomly allocated to a questionnaire with a hypothetical baseline risk of developing PsA of 50%, 70% or 90%. All participants went through the same introduction with explanation and an example question. We used a probabilistic threshold technique to investigate the PsO patients' preferences for interventions to prevent PsA, in which they chose between no treatment (no benefit and no risks) or a preventive intervention (pharmacological treatment or lifestyle intervention). Treatment attributes included the chance of mild, moderate and severe side effects, of which participants made a series of choices to find the maximum level of risk at which they would accept the intervention. Subgroup differences were analysed using the Fisher-Freeman-Halton Exact Test. <h3>Results:</h3> Between November 9<sup>th</sup> 2022 and November 14<sup>th</sup> 2023, 285 PsO patients initiated the survey. 155 participants completed the survey, but 46 of these only completed the sections up to moderate side effects. Mean age was 46.8 (SD 15.3) and 76% were female. 68% had a diagnosis of PsO for &gt;10 years and 28% had a first degree relative with PsA. 25% used tablets or injections as treatment for PsO. 143 out of 155 participants (92%) would consider a preventive pharmacological intervention to lower the risk of development of PsA. Overall, the maximum acceptable risk of developing PsA after initiating a hypothetical preventive therapy was on average 45% (IQR 30-50%). The acceptable risk was lower in the subgroup of PsO patients with a 50% baseline risk of developing PsA. See Figure 1. Participants were even more willing to start lifestyle interventions to lower their risk of developing PsA. A risk of developing PsA after lifestyle interventions of ≥30% was accepted by 89% of participants. The maximum accepted risk of mild side effects was on average 30% (IQR 20-50%), with a slightly lower acceptable risk level in the subgroup with a baseline risk of 50%. The maximum accepted risk of moderate side effects was on average 25% (IQR 10-40%), with no difference between subgroups. See Figure 2. We also found an overall tendency to accept severe side effects. Two third of the participants were willing to accept a risk of severe side effects of 10 in 100.000 patients. <h3>Conclusion:</h3> The willingness of PsO patients to start therapy to prevent PsA in our study is higher than previous results found for healthy people at risk of developing rheumatoid arthritis and axial spondyloarthritis [2]. This study provides a support for the acceptability of a clinical trial to prevent PsA in PsO patients when improved risk profiling becomes available, as many patients showed willingness to start preventive interventions even if these would come with a risk of side effects. <h3>REFERENCES:</h3> [1] Zabotti et al. Rheumatol Ther. 2021;8(4):1519-1534. [2] Van Boheemen et al. Arthritis Res Ther. 2020;22(1):217. <h3>Acknowledgements:</h3> This work is partly funded by HIPPOCRATES which received funding from the Innovative Medicines Initiative 2 Joint Undertaking (JU) under grant agreement No. 101007757. The JU receives support from the European Union's Horizon 2020 research and innovation programme and EFPIA. <h3>Disclosure of Interests:</h3> <b>None declared.</b>