Assessment of disease activity.

The objective of this study was to select a simple, feasible and validated core set of variables for the assessment of disease activity in systemic sclerosis. The subcommittee members extensively reviewed the studies in which the disease activity had been assessed, and analysed the construct validity and the feasibility of the criteria used in each study. The subcommittee members agreed on the possible use of either the European Scleroderma Study Group (ESSG) criteria for disease activity in SSc or the evaluation of selected cytokines and cell activation markers, found to be associated with distinct organ system involvement in recent studies. Despite the potential usefulness of cytokines and activation markers, most participants in the plenary session retained that their evaluation is not feasible in a number of centres, and their construct validity has not yet been assessed. The ESSG criteria for disease activity can be used for the time being to assess disease activity in clinical investigation studies as well as in clinical practice.