Background The 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.

Objectives To improve the clinical interpretation of the ACR-CRISS by creating a continuous ranked score of clinically and patient meaningful changes of its individual measures.

Methods Following 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.

Results Eighty 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.

Conclusion This 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.

References [1]Khanna D, et al. A&R 2016;68:299–311

[2]Hansen P, Ombler F. Multi-Criteria Decis. Anal 2008;15:87–107

Acknowledgements DK and FDG are recognised as joint senior authors. The authors acknowledge the doctors and patients involved in the Linear Criss working group: Giuseppina Abignano, Paolo Airò, Dina-Marie Aiuto, Yannick Allanore, Shervin Assassi, Jérôme Avouac, Gianluca Bagnato, Alexandra Balbir-Gurman, Silvia Bellando Randone,Lorenzo Beretta, Elana Bernstein, Silvia Laura Bosello, Yolanda Braun Moscovici, Katrina Brown, Maya Buch, Corrado Campochiaro, Patricia Carreira, Lorinda Chung, Julia Coakes, Mary Cox, Giovanna Cuomo, Maurizio Cutolo, Laszlo Czirjak, Lorenzo Dagna, Giacomo De Luca, Nicoletta Del Papa, Christopher Denton, Emma Derrett-Smith, Robyn Domsic, Raluca-Bianca Dumitru, Victoria Flower, Ivan Foeldvari, Armando Gabrielli, Yasir Ghaffar, Roberto Giacomelli, Dilia Giuggioli, Daisy Gonzalez, Jessica Gordon, Yvonne Gouldstone, Marie Hudson, Francesca Ingegnoli, Lorraine Jackson, Sergio Jimenez, Terrance Johnson, Bashar Kahaleh, Robin King, Otylia Kowal-Bielecka, Masataka Kuwana, Maria Lazzaroni, Alain Lescoat, Takashi Matsushita, Marco Matucci Cerinic, Maureen Mayes, Thomas Medsger, Francesca Menegazzi, Tünde Minier, Mandana Nikpour, Chris O’Hora, Emese Paári-Molnár, John Pauling, Jose Antonio Pereira da Silva, Mercè Piñero Vegas, Janet Pope, Susanna Proudman, Ismaila Rafiq, Valeria Riccieri, Tatiana Sofia Rodriguez-Reyna, Tânia Santiago, James Seibold, Richard Silver, Robert Spiera, Tracy Stafford, Virginia Steen, Yossra Atef Suliman. Madelon Vonk, Ian Wright.

Disclosure of Interests Lesley-Anne Bissell Speakers bureau: UCB, Abbvie, Galapagos, Daniel Furst: None declared, Sindhu Johnson: None declared, Paul Hansen: None declared, Esmeralda Recalde: None declared, Dinesh Khanna: None declared, Francesco Del Galdo Speakers bureau: Abbvie, AstraZeneca, Boehringer-Ingelheim, Capella Biosciences, Chemomab LTD, Janssen, Kymab LTD, Mitsubishi-Tanabe., Consultant of: Abbvie, AstraZeneca, Boehringer-Ingelheim, Capella Biosciences, Chemomab LTD, Janssen, Kymab LTD, Mitsubishi-Tanabe., Grant/research support from: Abbvie, AstraZeneca, Boehringer-Ingelheim, Capella Biosciences, Chemomab LTD, Janssen, Kymab LTD, Mitsubishi-Tanabe.