title: Validation of disease activity indices using the 28 joint counts in systemic sclerosis.
abstract: OBJECTIVE
  To validate the Disease Activity Score 28 using ESR (DAS28-ESR) and CRP (DAS28-CRP), the Simplified Disease Activity Index and the Clinical Disease Activity Index used in RA for SSc patients.
  
  
  METHODS
  Seventy-seven SSc patients, 40 RA patients, 20 patients with primary RP (PRP) and 28 healthy volunteers were assessed. Besides the disease activity composite indices, the European Scleroderma Study Group Activity Index (EScSG-AI), the HAQ-DI, the Cochin Hand Function Scale and the Short Form Health Survey (SF36) were evaluated. The validation procedure included the assessment for truth, discrimination and feasibility.
  
  
  RESULTS
  DAS28-ESR, DAS28-CRP, Simplified Disease Activity Index and Clinical Disease Activity Index showed significant correlation with EScSG-AI, HAQ-DI, Cochin Hand Function Scale and the physical component of SF36 (P < 0.001). All four indices discriminated patients with SSc from RA, PRS and healthy controls, respectively (P < 0.01). With the exception of DAS28-CRP, the other three indices also discriminated between subgroups of SSc based on value of EScSG-AI (⩽3 and >3) (P < 0.05). All four disease activity composite indices showed a good inter- and intraobserver reliability based on repeated measures of two independent investigators (P < 0.001).
  
  
  CONCLUSIONS
  All four disease activity composite indices were found to be valid measures for assessing arthritis in SSc. DAS28-ESR showed the best performance regarding reliability and construct validity.
authors.affiliation: Department of Rheumatology and Immunology, Medical Center.
authors.forename: Veronika
authors.initials: V
authors.lastname: Lóránd
authors.affiliation: Department of Rheumatology and Immunology, Medical Center.
authors.forename: Zsófia
authors.initials: Z
authors.lastname: Bálint
authors.affiliation: Department of Rheumatology and Immunology, Medical Center.
authors.forename: Dalma
authors.initials: D
authors.lastname: Komjáti
authors.affiliation: Department of Rheumatology and Immunology, Medical Center.
authors.forename: Balázs
authors.initials: B
authors.lastname: Németh
authors.affiliation: Department of Rheumatology and Immunology, Medical Center.
authors.forename: Tünde
authors.initials: T
authors.lastname: Minier
authors.affiliation: Department of Rheumatology and Immunology, Medical Center.
authors.forename: Gábor
authors.initials: G
authors.lastname: Kumánovics
authors.affiliation: Department of Rheumatology and Immunology, Medical Center.
authors.forename: Nelli
authors.initials: N
authors.lastname: Farkas
authors.affiliation: Department of Rheumatology and Immunology, Medical Center.
authors.forename: László
authors.initials: L
authors.lastname: Czirják
authors.affiliation: Department of Rheumatology and Immunology, Medical Center czirjak.laszlo@pte.hu.
authors.forename: Cecília
authors.initials: C
authors.lastname: Varjú
mesh_terms: D001172:Arthritis, Rheumatoid / Q000150:complications / Q000473:pathology*; D004185:Disability Evaluation; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007596:Joints / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012595:Scleroderma, Systemic / Q000150:complications / Q000473:pathology*; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires
keywords: DAS28.; arthritis; disease activity; scleroderma; systemic sclerosis; validation