Disease activity indices in systemic sclerosis: a systematic literature review.

Reviewing disease activity indices (DAI) in systemic sclerosis (SSc) and reporting their validation status.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.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.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.