Improving agreement in assessment of synovitis in rheumatoid arthritis

Synovitis assessment through evaluation of swollen joints is integral in steering treatment decisions in rheumatoid arthritis (RA). However, there is high inter-observer variation. The objective was to assess if a short collegiate consensus would improve swollen joint agreement between rheumatologists and whether this was affected by experience.

Eighteen rheumatologists from French university rheumatology units participated in three 30 minutes rounds over a half day meeting evaluating joint counts of RA patients in small groups, followed by short consensus discussions. Agreement was evaluated at the end of each round as follows: (i) global agreement of swollen joints (ii) swollen joint agreement according to level of experience of the rheumatologist (iii) swollen joint count and (iv) agreement of disease activity state according to the Disease Activity Score (DAS28). Agreement was calculated using percentage agreement and kappa.

Global agreement of swollen joints failed to improve (kappa 0.50 to 0.52) at the joint level. Agreement between seniors did not improve but agreement between newly qualified rheumatologists and their senior peer, which was initially poor (kappa 0.28), improved significantly (to 0.54) at the end of the consensus exercises. Concordance of DAS28 activity states improved from 71% to 87%.

Consensus exercises for swollen joint assessment is worthwhile and may potentially improve agreement between clinicians in clinical synovitis and disease activity state, benefit was mostly observed in newly qualified rheumatologists.