SAT0649 DEVELOPMENT AND VALIDATION OF A PATIENT-REPORTED OUTCOME ASSESSING ACTIVITY LIMITATION AND PARTICIPATION RESTRICTION OF PATIENTS WITH SYSTEMIC SCLEROSIS: THE COCHIN 17-ITEM SCLERODERMA FUNCTIONAL SCALE (CSF-17)

Abstract

Background: Few patient-reported outcomes measures (PROs) have been specifically designed to assess the functioning of patients with systemic sclerosis (SSc). In addition, the development of currently available instruments did not fully follow current guidelines (1) Objectives: To develop and validate a PRO assessing activity limitation and participation restriction of patients with SSc. Methods: A provisional International Classification of Functioning, Disability and Health (ICF)-based 65-item questionnaire previously developed from interviews of SSc patients was submitted online to French patients (n=184) of the Scleroderma Patient-centered Intervention Network e-cohort (2). Items were reduced according to their metric properties, dimensional structure of the questionnaire was assessed by principal component analysis, convergent and divergent validities using the Spearman correlation coefficient (ρ), internal consistency by the Cronbach α coefficient and reliability by a test-retest method using intraclass correlation coefficient (ICC) and Bland and Altman analysis. Results: Overall, 113/184 (61.4%) patients completed the provisional questionnaire. The item-reduction process resulted in a 17-item questionnaire, the Cochin 17-item Scleroderma Functional scale (CSF-17). Principal component analysis extracted 2 dimensions: 10 items related to mobility (CSF-17 section A) and 7 items related to general tasks (CSF-17 section B). We observed convergent validity with global activity limitation, pain, depression and aesthetic burden and divergent validity with anxiety. The Cronbach α coefficient was 0.94 for section A and 0.95 for section B. ICC (n=25 patients) was 0.92 for CSF-17 total score. Bland and Altman analysis did not reveal a systematic trend for the test-retest. Conclusion: The CSF-17 is a self-administered questionnaire assessing activity limitation and participation restriction of patients SSc with good content and construct validities References [1] Health USDo, Human Services FDA, Research, et al. Guidance for industry: patient-reported outcome measures: use in medical product development to support labeling claims: draft guidance. Health Qual Life Outcomes. 2006;4:79. [2] Kwakkenbos L, Jewett LR, Baron M, Bartlett SJ, Furst D, Gottesman K, et al. The Scleroderma Patient-centered Intervention Network (SPIN) Cohort: protocol for a cohort multiple randomised controlled trial (cmRCT) design to support trials of psychosocial and rehabilitation interventions in a rare disease context. BMJ Open. 2013;3(8). Acknowledgement: Dr Camille Daste received a Master 2 grant from the French Society of Rheumatology Disclosure of Interests: None declared