title: Development of the ClinESSDAI: a clinical score without biological domain. A tool for biological studies.
abstract: OBJECTIVE
  To develop and validate ClinESSDAI (Clinical European League Against Rheumatism Sjögren's Syndrome Disease Activity Index), ie, ESSDAI without the biological domain.
  
  
  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.
authors.affiliation: Assistance Publique-Hôpitaux de Paris, Université Paris-Sud, (AP-HP), Service de Rhumatologie, Hôpitaux Universitaires Paris-Sud, Center of Research on Immunology of Viral and Autoimmune diseases (IMVA), Le Kremlin Bicêtre, France.
authors.forename: Raphaèle
authors.initials: R
authors.lastname: Seror
authors.affiliation: Department of Oral and Maxillofacial Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Petra
authors.initials: P
authors.lastname: Meiners
authors.affiliation: Faculty of Medicine, AP-HP, Hôtel Dieu Hospital, Centre of Clinical Epidemiology, University of Paris Descartes,Paris, France.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Baron
authors.affiliation: Department of Rheumatology and Clinical Immunology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Hendrika
authors.initials: H
authors.lastname: Bootsma
authors.affiliation: Rheumatology Department, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK.
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Bowman
authors.affiliation: Sections of Rheumatology, Instituto San Giuseppe, Como and Casa di Cura di Lecco, Lecco, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Vitali
authors.affiliation: Department of Rheumatology, Centre National de Référence des Maladies Auto-Immunes Rares, INSERM UMRS_1109, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg university Hospital, Université de Strasbourg, Strasbourg, France.
authors.forename: Jacques-Eric
authors.initials: JE
authors.lastname: Gottenberg
authors.affiliation: Department of Rheumatology, Skane University Hospital Malmö, Lund University, Malmö, Sweden.
authors.forename: Elke
authors.initials: E
authors.lastname: Theander
authors.affiliation: Department of Pathophysiology, School of Medicine, University of Athens, Athens, Greece.
authors.forename: Athanasios
authors.initials: A
authors.lastname: Tzioufas
authors.affiliation: Department of Medical and Biological Sciences, Clinic of Rheumatology, Udine University, Udine, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: De Vita
authors.affiliation: Laboratory of Autoimmune Diseases 'Josep Font', CELLEX-IDIBAPS, Department of Autoimmune Diseases, ICMiD, Hospital Clinic, Barcelona, Spain.
authors.forename: Manel
authors.identifier: http://orcid.org/0000-0001-5709-6734
authors.initials: M
authors.lastname: Ramos-Casals
authors.affiliation: Rheumatology Department, Charité, University Hospital, Berlin, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Dörner
authors.affiliation: Department of Medical and Biological Sciences, Clinic of Rheumatology, Udine University, Udine, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Quartuccio
authors.affiliation: Faculty of Medicine, AP-HP, Hôtel Dieu Hospital, Centre of Clinical Epidemiology, University of Paris Descartes,Paris, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Ravaud
authors.affiliation: Assistance Publique-Hôpitaux de Paris, Université Paris-Sud, (AP-HP), Service de Rhumatologie, Hôpitaux Universitaires Paris-Sud, Center of Research on Immunology of Viral and Autoimmune diseases (IMVA), Le Kremlin Bicêtre, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Mariette
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D011594:Psychometrics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D012859:Sjogren's Syndrome / Q000175:diagnosis*
keywords: Disease Activity; Outcomes research; Sjøgren's Syndrome