ASSESSING THE QUALITY OF BIOLOGIC SWITCH DECISIONS IN PSORIATIC ARTHRITIS: DEVELOPMENT AND VALIDATION OF OUTCOMES MEASUREMENT TOOSL.

Background: Psoriatic arthritis (PsA) is a chronic inflammatory disease commonly managed by rheumatologists. Switching between biologic therapies is a re - commended strategy for PsA patients that show insufficient response or adverse events with a biologic agent. Although the choice of the subsequent biologic may be dependent on many factors (accessibility, clinical aspects, patient's preference), assessing the quality of the switch decision is of utmost relevance. Objectives: To develop and validate two outcomes measurement tools to evaluate the quality of biologic therapies switch in PsA patients with axial and peri - pheral phenotypes in clinical practice. Methods: A Task Force and an Expert Panel were specifically assembled for this purpose. The tool development comprised a modified-Delphi method in a four-step procedure: 1) literature search and experts' opinion collection about quality indicators for PsA management; 2) Delphi design to address the deve - lopment of the measurement tool; 3) three Delphi questionnaire rounds; 4) consensus meeting to discuss the results and reach a decision regarding outcomes measurement tools' components. This phase resulted in the definition of two measurement tools to evaluate the quality of biologic switch in peripheral and axial PsA. For the validation of these tools, 12 experienced rheumatologists were asked to evaluate and classify the biologic switch of 80 patient profiles (40 with peri - pheral PsA and 40 with axial PsA phenotypes). Clinical judgement was defined as the "gold standard" against which, tools' output was compared. Each patient profile was evaluated by 3 experts and only those with consensual clinical judgment (agreement between at least 2 of 3 rheumatologists) were included in the validation analysis. The results were used to assess the validity (by sensitivity/specificity analysis) and the reliability, more specifically inter-rater reliability, (by Cohen's kappa) of both tools. Results: The developed tools consisted of 6 domains (disease activity, dactylitis, enthesitis, skin and nail manifestations, physical function and quality of life), their respective instruments and thresholds. The classification of the biologic switch was divided into three quality levels: "Good", based on treat-to-target thresholds; "Moderate", based on improvement from baseline thresholds; and the remaining as "Insufficient". In the validation phase, an agreement (i.e. clinical judgement versus tools' output) of 75% was obtained for peripheral PsA and 63% for axial PsA. The peripheral PsA tool was found to be more sensitive (92%) with the "Good" quality level and more specific (97%) with the "Insufficient" quality level. Regarding the axial PsA tool, higher sensitivity and specificity was obtained for all quality levels, as well as a higher Cohen's kappa than Peripheral PsA tool (0.94 vs 0.71). Conclusion: The two developed outcomes measurement tools address the quality of treatment decisions regarding biologics' switch in PsA clinical practice. The data in the validation part support the tools' reliability for both peripheral and axial PsA and could complement clinical judgment too. Therefore, these fully developed and validated tools are expected to support rheumatologists in making better and more informed therapeutic decisions. Disclosure of Interest: This publication was deve - loped under the project "Switch to Quality: Psoriatic Arthritis biologic switching consensus" that was sponsored by Novartis and executed with the collaboration of IQVIA. Acknowledgments: To all rheumatologists who collaborated in the clinical judgement. [ABSTRACT FROM AUTHOR]