Pos1419 Eular Scleroid as Comprehensive Patient Reported Outcome in Systemic Sclerosis: Longitudinal Validation of Content Validity and Sensitivity to Change

Background: Patient-reported outcomes (PROs) are a crucial aspect of assessing disease activity. Systemic Sclerosis (SSc) is a multisystem disease where multiple PROs have been historically utilised in the attempt to capture the overall burden of disease, including the Health Assessment Questionnaire Disability Index (HAQ-DI), Cochin Hand Function Scale (CHFS), BORG, and the University of California Los Angeles Scleroderma Clinical Trials Consortium gastrointestinal tract 2.0 (GIT 2.0), among others. The EULAR Systemic Sclerosis Impact of Disease (ScleroID) questionnaire is a comprehensive PRO, recently developed with strong input from patients with the purpose of capturing all the disease manifestations that matter the most to patients and it includes, Raynaud, hand function, upper gastrointestinal, pain, fatigue, lower gastrointestinal, life choices and activity limitation, body mobility, dyspnea, and digital ulcer domains 1. Objectives: To determine whether ScleroID and its domains correlate with clinical characteristics and PROs cross-sectionally and over 12 months, and to assess the ScleroID thresholds corresponding to the published Minimal Clinically Important Difference (MCID) in overall Disability Index as assessed by HAQ-DI. Methods: Patients from the observational cohort STRIKE enrolled between January 2022 and August 2023 were included in the study. Demographic and clinical data of the patients were recorded. Spearman's rank correlation was used to analyse correlations between ScleroID and its dimensions and PROs, as well as modified Rodnan skin score (mRSS) and Forced Vital Capacity (FVC) % predicted. Changes (Δ) in scores were calculated as the difference between follow-up and baseline scores. MCID for ScleroID was evaluated according to the validated threshold of HAQ-DI by ROC curve analysis. IBM SPSS for Mac (version 26.0) was used for the statistical analyses. Results: A total of 282 patients were available for baseline analysis and 75 patients were available for 12 months follow-up. At baseline, 81 (28.7%) patients had very early diagnosis of SSc (VEDOSS), 129 (45.7%) limited SSc, and 72 (25.5%) diffuse SSc. The median ScleroID total score was 1.7 (ranges 0.9-4.8) in VEDOSS, 3.2 (ranges 1.1-5.7) in limited SSc and 4.5 (ranges 2.4-6.8) in diffuse SSc (p Conclusion: EULAR ScleroID promises to be an extremely valuable PRO for an overall assessment of SSc, across VEDOSS, limited and diffuse cutaneous SSc. The correlation of the single domains with validated PROs and its sensitivity to change over time do support the use of ScleroID as a key composite PRO in Randomised Controlled Trials. Validation of EULAR ScleroID MCIDs in different disease subsets is warranted for its use as patient meaningful changes in disease activity. REFERENCES: 1 Development and validation of a patient-reported outcome measure for systemic sclerosis: the EULAR Systemic Sclerosis Impact of Disease (ScleroID) questionnaire. Becker MO, et al. Ann Rheum Dis 2022;81:507–515. 2 Characteristics of ScleroID highlighting musculoskeletal and internal organ implications in patients afflicted with systemic sclerosis. Nagy G, et al. Arthritis Res Ther. 2023 May 20;25(1):84. 3 Validation and assessment of minimally clinically important difference of the unadjusted Health Assessment Questionnaire in a Danish cohort: uncovering ordinal bias. Ørnbjerg LM, et al. Scand J Rheumatol. 2020 Jan;49(1):1-7. Acknowledgements: NIL. Disclosure of Interests: Seda Colak: None declared, Stefano Di Donato: None declared, Lesley Anne Bissell: None declared, Theresa Barnes: None declared, Christopher P Denton: None declared, Muhammad Nisar: None declared, Vishal Kakkar: None declared, Francesco Del Galdo Astrazeneca, Janssen, Janssen, Astrazeneca, Mitsubishi-Tanabe, Cappella bioscience, AbbVie, Astrazeneca, Boehringer-Ingelheim, Janssen, GSK.