Activity and Damage Indices for Sjögren's Disease

Primary Sjögren's disease (SjD) is a systemic autoimmune disease with heterogeneous clinical manifestations, ranging from isolated glandular dysfunction to multisystem involvement and severe complications. This variability complicates disease management, particularly the assessment of disease activity and long-term outcomes. Disease activity in SjD encompasses both systemic manifestations and patient-reported outcomes (PROs). The EULAR Sjögren's Syndrome Disease Activity Index (ESSDAI) remains the standard for systemic activity, while the ESSPRI complements these scores by capturing subjective symptom burden. These tools have limitations because they do not evaluate the same manifestations of SjD and may therefore respond differently to treatment. Thus, composite outcomes such as the Sjögren's Tool for Assessing Response (STAR) and the Composite of Relevant Endpoints for Sjögren Syndrome (CRESS) have been developed. They integrate improvements in ClinESSDAI, PROs, biological parameters and objective dryness, providing a more comprehensive measure of disease activity. Assessment of damage, defined as irreversible sequelae, remains an unmet need in SjD. Damage is a reflection of the natural evolution of the disease, and is also relevant to measuring the impact and health economic effects of therapeutic interventions. Existing measures, including cumulative ESSDAI, track longitudinal activity and reflect the severity of the disease, but do not specifically capture damage. In summary; SjD assessment requires complementary tools for systemic activity and PROs, with composite scores a recent innovation. An important remaining gap is a validated method to evaluate damage, essential to fully evaluate disease progression.