OP0224 CONTINUOUS COMPOSITE MEASURES FOR ROUTINE CARE IN PSORIATIC ARTHRITIS: THRESHOLDS OF MEANING AND CLINICALLY IMPORTANT DIFFERENCE ESTIMATES FOR THE 3 AND 4 VAS SCALES FROM A UK MULTICENTRE STUDY

Background: There is a recognised need for continuous composite measure of disease activity the assessment Psoriatic Arthritis (PsA) in routine clinical settings to allow objective response and implementation treat target. 1 Longer multidimensional measures are considered less feasible care number shorter have been proposed including, Disease Activity Score (DAPSA), 28 (DAS28), 3 Visual Analogue Scale (VAS) (comprising physician global VAS, patient VAS skin VAS) or 4 pain joint VAS). Testing these trial datasets has suggested but thresholds meaning not established. 2 Objectives: To estimate clinically relevant improvement practice PsA. Methods: Clinical reported outcome were assessed patients fulfilling CASPAR criteria PsA at three consecutive follow up visits UK multicentre observational study. Participants underwent completed including health anchor questions. Estimates Minimal Detectible Change (MDC) derived using 1.96*2*Standard Error Mean (SEM). Clinically Important Difference (MCID) method two distribution methods (Table 1). Thresholds low, moderate high triangulated from established cut-off values PASDAS DAPSA. Table 1. detectable change ANCHOR (MEDIAN) DISTRIBUTION#1 DISTRIBUTION #2 MDC CPDAI 0.5 1.49 1.5 4.16 GRACE 0.26 0.6 0.77 2.18 1.22 0.64 0.76 1.58 DAS28 0.2 0.85 0.62 1.46 3VAS 1.13 1.16 0.91 3.12 4VAS 1.11 0.96 0.94 2.45 DAPSA 7.25 9.09 10.40 35.63 (DAPSA); (PASDAS); Composite Index (CPDAI); (DAS28). Distribution #1: Baseline standard deviation (sd) * √ – Cronbach’s alpha #2: baseline sd (MDC): 1.96*2*SEM where SEM = √1 - ICC Results: 139 subjects recruited (59 male, 80 female, mean (range) age (years) 52.7 (19 83), duration psoriasis 21.9 (2 71), psoriatic arthritis 6.1 (0 41). Cut-off 1.3, 2.4, 4.8 Vas 1.6, 2.8 5.0 (Figure MCID Conclusion: We report estimates improvements scales. The can now be tested independent datasets. References: [1]Coates et al 2018 A&R Mar;70(3):345-355. [2]Tillett W 2021 J Rheum In Press Acknowledgements Funding: This research funded by National Institute Health Research, Programme Grants Applied Research [Early detection improve with undiagnosed (‘PROMPT’), RP-PG-1212-20007]. views expressed those authors necessarily NIHR Department Social Care. Disclosure Interests: William Tillett Speakers bureau: AbbVie, Amgen, Celgene, Lilly, Janssen, Novartis, MSD, Pfizer, UCB, Consultant of: BMS, Grant/research support from: UCB., Julia Day: None declared, Neil McHugh: Oliver FitzGerald Laura C Coates Biogen, Gilead, Eli Medac, Boehringer Ingelheim, Bristol-Myers Squibb, Philip Helliwell: declared