Responsiveness in rheumatoid arthritis. a report from the OMERACT 11 ultrasound workshop.

Objective: To summarize the work performed by the Outcome Measures in Rheumatology (OMERACT) Ultrasound (US) Task Force on the validity of different US measures in rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA) presented during the OMERACT 11 Workshop.

Methods: The Task Force is an international group aiming to iteratively improve the role of US in arthritis clinical trials. Recently a major focus of the group has been the assessment of responsiveness of a person-level US synovitis score in RA: the US Global Synovitis Score (US-GLOSS) combines synovial hypertrophy and power Doppler signal in a composite score detected at joint level. Work has also commenced examining assessment of tenosynovitis in RA and the role of US in JIA.

Results: The US-GLOSS was tested in a large RA cohort treated with biologic therapy. It showed early signs of improvement in synovitis starting at Day 7 and increasing to Month 6, and demonstrated sensitivity to change of the proposed grading. Subsequent voting questions concerning the application of the US-GLOSS were endorsed by > 80% of OMERACT delegates. A standardized US scoring system for detecting and grading severity of RA tenosynovitis and tendon damage has been developed, and acceptable reliability data were presented from a series of exercises. A preliminary consensus definition of US synovitis in pediatric arthritis has been developed and requires further testing.

Conclusion: At OMERACT 11, consensus was achieved on the application of the US-GLOSS for evaluating synovitis in RA; and work continues on development of RA tenosynovitis scales as well as in JIA synovitis.