Objective To develop and validate ClinESSDAI (Clinical European League Against Rheumatism Sjögren's Syndrome Disease Activity Index), ie, ESSDAI without the biological domain.
Patients and methods The 702 fictive vignettes derived from 96 real cases of primary Sjögren's syndrome of the ESSDAI development study were used. As for ESSDAI development, the physician assessment of disease activity (0–10 scale) was used as the ‘gold standard’ in a multivariate model for weighting domains, after removing the biological domain. The reliability, assessed by intraclass correlation coefficient (ICC) between ClinESSDAI and ESSDAI, explored if ClinESSDAI was equivalent to ESSDAI. Its psychometric (ie, measurement) properties were compared with that of ESSDAI in an independent cohort. Also, its use was evaluated on data of two clinical trials.
Results In multivariate modelling, all 11 domains remained significantly associated with disease activity, with slight modifications of some domain weights. Reliability between clinESSDAI and ESSDAI was excellent (ICC=0.98 and 0.99). Psychometric properties of clinESSDAI, disease activity levels and minimal clinically important improvement thresholds and its ability to detect change over time in clinical trials were very close to that of ESSDAI.
Conclusions ClinESSDAI appears valid and very close to the original ESSDAI. This score provides an accurate evaluation of disease activity independent of B-cell biomarkers. It could be used in various circumstances: (i) in biological/clinical studies to avoid data collinearity, (ii) in clinical trials, as secondary endpoint, to detect change independent of biological effect of the drug, (iii) in clinical practice to assess disease activity for visits where immunological tests have not been done.
- Disease Activity
- Sjøgren's Syndrome
- Outcomes research
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Handling editor Tore K Kvien
Collaborators Members of the EULAR Sjögren's Task Force who participated in this study: Elena Bartoloni and Roberto Gerli, Rheumatology Unit, Department of Clinical & Experimental Medicine, University of Perugia, Italy; Stefano Bombardieri, Rheumatology Unit, Department of Internal Medicine, University of Pisa, Italy; Hendrika Bootsma, Cees Kallenberg and Petra Meiners, Department of Rheumatology and Clinical Immunology, University Medical Center Groningen (UMCG), Groningen, Netherlands Simon J Bowman, Rheumatology Department, University Hospital Birmingham, Birmingham, UK, Johan G Brun, Department of Rheumatology, Haukeland University Hospital, Bergen, Norway; Roberto Caporali, Department of Rheumatology, University of Pavia, IRCCS S. Matteo Foundation, Pavia, Italy; Salvatore De Vita, Clinic of Rheumatology, University Hospital of Udine, University of Udine, Udine, Italy; Valerie Devauchelle and Alain Saraux, Rheumatology Department, la Cavale Blanche Teaching Hospital, Brest, France; Thomas Dörner, Rheumatology Department, Charité, University Hospital Berlin, Berlin, Germany; Anne-Laure Fauchais, Department of Rheumatology, University Hospital, Limoges, France; Jacques Eric Gottenberg, Department of Rheumatology, Strasbourg University Hospital, Strasbourg, France; Eric Hachulla, Department of Internal Medicine, Claude Huriez Hospital, Lille, France; Aike A Kruize, Departments of Rheumatology & Clinical Immunology, University Medical Center, Utrecht, The Netherlands; Thomas Mandl and Elke Theander, Department of Rheumatology, Malmö University Hospital, Lund University, Sweden; Xavier Mariette, Frederic Demoulins and Raphaèle Seror, Department of Rheumatology, Bicetre Hospital, Le Kremlin Bicêtre, France; Carlomaurizio Montecucco, Department of Rheumatology, University of Pavia, Pavia, Italy; Wan-Fai Ng, Musculoskeletal research group, University of Newcastle, Newcastle, UK; Sonja Praprotnik and Matija Tomsic, Department of Rheumatology, University Medical Centre, Ljubljana, Slovenia; Manel Ramos Casals, Laboratory of Autoimmune Diseases ‘Josep Font’, Hospital Clinic, Barcelona, Spain; Philippe Ravaud, Center of Clinical Epidemiology, Hopital Hotel Dieu, Paris, France; Hal Scofield and Kathy L. Sivils, Arthritis and clinical immunology, Oklahoma Medical research foundation, Oklahoma City, USA; Roser Solans Laqué, Department of Autoimmune systemic Diseases, Valld'Hebron University Hospital, Barcelona, Spain; Takayuki Sumida, Department of Internal Medicine, University of Tsukuba, Japan; Sumusu Nishiyama, Rheumatic Disease Center, Kurashiki Medical Center, Kurashiki, Japan; Athanasios Tzioufas, Department of Pathophysiology, School of Medicine, University of Athens, Greece, Guido Valesini, Rheumatology Unit, Department of Clinical & Experimental Medicine, Sapienza University of Rome, Rome, Italy; Valeria Valim, Division of Rheumatology, Department of Medicine, Federal University of Espírito Santo, Brazil; Claudio Vitali, Department of Internal Medicine and section of Rheumatology, ‘Villamarina’ Hospital, Piombino, Italy, Cristina Vollenweider, Department of Rheumatology, German Hospital, Buenos-Aires, Argentina.
Contributors Conception and design: RS, PR, SJB, XM, HB. Acquisition of data: all authors. Analysis and interpretation of data: RS, GB, PM, SJB, XM, PR. Drafting the article or revising it critically for important intellectual content: all authors. Final approval of the version published: all authors.
Funding This work is a part of a project conducted by the EULAR Sjögren's task force. This project has been endorsed and supported by EULAR (project code CLI 010). The Beliss study was sponsored by AP-HP (Assistance Publique-Hopitaux de Paris) and by the Azienda Ospedaliero Universitaria ‘Santa Maria della Misericordia’, Udine, Italy. It received an unrestricted research grant from Human Genome Science/GlaxoSmithKline. The Rituximab trial from Netherlands is an investigator-driven study and was financially supported by Roche, Woerden, The Netherlands, which supplied the study medication. There was no involvement of this funding source in study design, patient recruitment, data collection, analysis and interpretation and writing of the report.
Competing interests None declared.
Patient consent Obtained.
Ethics approval The Institutional Review Board of GHU Paris Nord (n° IRB0006477).
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Data are available on request.