POS0868 THE DEVELOPMENT OF THE LINEAR CRISS; A CLINICAL AND PATIENT MEANINGFUL ANCHOR TO THE ACR-CRISS IN SCLERODERMA.

Abstract

BackgroundThe ACR Composite Response Index in Systemic Sclerosis (ACR-CRISS) is one of the first composite outcome measures in diffuse cutaneous Systemic sclerosis (dcSSc).1 It relies on validated clinical domains selected through a data-driven methodology; however, it only provides a probability of response and is unable to differentiate between patients who do not improve and who worsen respectively.ObjectivesTo improve the clinical interpretation of the ACR-CRISS by creating a continuous ranked score of clinically and patient meaningful changes of its individual measures.MethodsFollowing OmerACT guidelines for outcome measurement development, relevant stakeholders were identified from 5 continents, including 100 physicians with proven experience in managing patients with dcSSc and 100 patients with dcSSc who have participated in at least one clinical trial. An adaptive conjoint analysis survey based on the PAPRIKA method2 and implemented using 1000minds software was administered. Patients and doctors were asked to choose which of two hypothetical patients had a better or worse outcome according to Minimally Clinical Important Differences (MCID) in two domains at a time from FVC, HAQ-DI and mRSS and the presence of organ failure. These pairwise choices were analysed to rank and weight the MCIDs against each other. With patient and public involvement, utilising a ‘think aloud’ approach, a video tutorial was produced explaining the objectives and process of the adaptive survey to the participants.ResultsEighty rheumatologists and 80 patients with dcSSc completed the survey, which ran from June 2020 to January 2021. From the survey, relative weights for the 4 domains, reflecting their relative importance with respect to improving and worsening outcomes, were determined. A continuous composite ranked score reflecting the relative weighting of the individual outcome measures (Ranked Composite Important Difference, RCID) was developed accordingly (Table 1). The score ranges from -1 (worst possible outcome) to 1 (best possible outcome), in patients who experience no organ failure and do not meet any MCID in any of the 3 domains scoring 0.Table 1.The relative median weights of each of the core set measures within the better and worse outcome models, expressed as a score from -1 to 1Worsening weightsImprovement weightsDoctorsPatientsCombinedDoctorsPatientsCombinedOrgan failure-0.355-0.333-0.326N/AN/AN/AFVC-0.324-0.306-0.3160.4630.4520.451mRSS-0.205-0.229-0.2170.3200.3200.324HAQ-DI-0.114-0.115-0.1410.2000.2270.224ConclusionThis collaborative process using a novel, robust methodology and involving both rheumatologists and patients has created a clinically and patient meaningful composite score that can be used as an anchor to the ACR-CRISS, or other clinical outcomes. Performance against the ACR-CRISS and revised CRISS in randomised controlled trials and in observational cohorts will determine the clinical value of the RCID.