title: Disease activity indices in systemic sclerosis: a systematic literature review.
abstract: OBJECTIVE
  Reviewing disease activity indices (DAI) in systemic sclerosis (SSc) and reporting their validation status.
  
  
  METHODS
  Literature was systematically reviewed on studies documenting the development of DAI, assessing the validation status of DAI and studies using a DAI in their analysis. The qualitative and quantitative validation status of existing DAI was assessed based on OMERACT and on definitions of the American College of Rheumatology (ACR) committee on quality measures.
  
  
  RESULTS
  Three DAI in SSc have been proposed in literature: the European Scleroderma Study Group (EScSG) activity index, the 12-point DAI and the Combined Response Index for Systemic Sclerosis (CRISS). The EScSG activity index is yet applied as an outcome measure in 48 different studies. The EScSG activity index and the CRISS are provisional partially validated DAI.
  
  
  CONCLUSIONS
  Future studies are needed to fully validate the EScSG activity index and the CRISS and to assess the validation status of the 12-point DAI.
authors.affiliation: Department of Internal Medicine, Faculty of Medicine and Health Sciences, Ghent University, Belgium. karin.melsens@ugent.be.
authors.forename: Karin
authors.initials: K
authors.lastname: Melsens
authors.affiliation: Department of Internal Medicine, Faculty of Medicine and Health Sciences, Ghent University; and Department of Rheumatology, Faculty of Medicine and Health Sciences, Ghent University, Belgium.
authors.forename: Filip
authors.initials: F
authors.lastname: De Keyser
authors.affiliation: Department of Internal Medicine, Faculty of Medicine and Health Sciences, Ghent University, Belgium.
authors.forename: Saskia
authors.initials: S
authors.lastname: Decuman
authors.affiliation: Department of Rheumatology, Faculty of Medicine and Health Sciences, Ghent University, Belgium.
authors.forename: Yves
authors.initials: Y
authors.lastname: Piette
authors.affiliation: Department of Cardiology, Ghent University Hospital, Belgium.
authors.forename: Els
authors.initials: E
authors.lastname: Vandecasteele
authors.affiliation: Department of Internal Medicine, Faculty of Medicine and Health Sciences, Ghent University; and Department of Rheumatology, Faculty of Medicine and Health Sciences, Ghent University, Belgium.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Smith
mesh_terms: D003661:Decision Support Techniques; D004185:Disability Evaluation; D006304:Health Status; D006305:Health Status Indicators; D006801:Humans; D017063:Outcome Assessment, Health Care / Q000379:methods*; D011237:Predictive Value of Tests; D011379:Prognosis; D011788:Quality of Life; D015203:Reproducibility of Results; D012595:Scleroderma, Systemic / Q000175:diagnosis* / Q000503:physiopathology / Q000523:psychology / Q000628:therapy; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires