Physician consensus and case analysis help establish new RA criteria

American College of Rheumatology and European League Against Rheumatism investigators who developed new classification criteria for rheumatoid arthritis (RA) used a consensus-based, decision analysis approach during phase 2 that included evaluation of case scenarios to identify predictive factors for persistent inflammatory or erosive arthritis. This approach was informed by and complemented their phase 1 efforts.

In phase 1, Aletaha and associates used cohort data to identify key factors to include in the new criteria and their relative importance. Phase 2 included the following 4 steps: assembly of an expert panel, development and rank ordering of patient case scenarios, a 2-day in-person consensus meeting, and assessment of face and construct validity.

The team identified 6 criteria that foretell of erosive arthritis in persons who have early synovitis. Two-synovitis in at least 1 joint and absence of another condition to explain it-are essential for defining RA. The other 4 criteria were key but of differing importance. The duration of morning stiffness was unimportant because it is nondiscriminatory.

The authors noted that their work in the first 2 phases informed a third phase, in which the final criteria set, including the cut point to be used to define definite RA, was determined.