Sjögren's syndrome disease damage index and disease activity index: Scoring systems for the assessment of disease damage and disease activity in Sjögren's syndrome, derived from an analysis of a cohort of Italian patients

Our findings indicate that the SSDDI is an adequate instrument to objectively measure damage in patients with SS, and that the SSDAI is a valid tool to measure disease activity when used either as a single-state index or as a transition index.