Factors influencing concordance between clinical and ultrasound findings in rheumatoid arthritis.

OBJECTIVE: Clinical joint examination (CJE) is less time-consuming than ultrasound (US) in rheumatoid arthritis (RA). Low concordance between CJE and US would indicate that the 2 tests provide different types of information. Knowledge of factors associated with CJE/US concordance would help to select patients and joints for US. Our objective was to identify factors associated with CJE/US concordance. METHODS: Seventy-six patients with RA requiring tumor necrosis factor-α (TNF-α) antagonist therapy were included in a prospective, multicenter cohort. In each patient, 38 joints were evaluated. Synovitis was scored using CJE, B-mode US (B-US), and power Doppler US (PDUS). Joints whose kappa coefficient (κ) for agreement CJE/US was < 0.1 were considered discordant. Multivariate analysis was performed to identify factors independently associated with CJE/US concordance, defined as factors yielding p < 0.05 and OR > 2. RESULTS: Concordance before TNF-α antagonist therapy varied across joints for CJE/US (κ = -0.08 to 0.51) and B-US/PDUS (κ = 0.30 to 0.67). CJE/US concordance was low at the metatarsophalangeal joints and shoulders (κ < 0.1). Before TNF-α antagonist therapy, a low 28-joint Disease Activity Score (DAS28) was associated with good CJE/B-US concordance, and no factors were associated with CJE/PDUS concordance. After TNF-α antagonist therapy, only the joint site was associated with CJE/B-US concordance; joint site and short disease duration were associated with CJE/PDUS concordance. CONCLUSION: Concordance between CJE and US is poor overall. US adds information to CJE, most notably at the metatarsophalangeal joints and shoulders. Usefulness is decreased for B-US when DAS28 is low and for PDUS when disease duration is short.

The ability of synovitis to predict structural damage in rheumatoid arthritis: a comparative study between clinical examination and ultrasound.

OBJECTIVES: To evaluate synovitis (clinical vs ultrasound (US)) to predict structural progression in rheumatoid arthritis (RA). METHODS: Patients with RA. STUDY DESIGN: Prospective, 2-year follow-up. DATA COLLECTED: Synovitis (32 joints (2 wrists, 10 metacarpophalangeal, 10 proximal interphalangeal, 10 metatarsophalangeal)) at baseline and after 4 months of therapy by clinical, US grey scale (GS-US) and power doppler (PD-US); x-rays at baseline and at year 2. ANALYSIS: Measures of association (OR) were tested between structural deterioration and the presence of baseline synovitis, or its persistence, after 4 months of therapy using generalised estimating equation analysis. RESULTS: Structural deterioration was observed in 9% of the 1888 evaluated joints in 59 patients. Baseline synovitis increased the risk of structural progression: OR=2.01 (1.36-2.98) p<0.001 versus 1.61 (1.06-2.45) p=0.026 versus 1.75 (1.18-2.58) p=0.005 for the clinical versus US-GS versus US-PD evaluation, respectively. In the joints with normal baseline examination (clinical or US), an increased probability for structural progression in the presence of synovitis for the other modality was also observed (OR=2.16 (1.16-4.02) p=0.015 and 3.50 (1.77-6.95) p<0.001 for US-GS and US-PD and 2.79 (1.35-5.76) p=0.002) for clinical examination. Persistent (vs disappearance) synovitis after 4 months of therapy was also predictive of subsequent structural progression. CONCLUSIONS: This study confirms the validity of synovitis for predicting subsequent structural deterioration irrespective of the modality of examination of joints, but also suggests that both clinical and ultrasonographic examinations may be relevant to optimally evaluate the risk of subsequent structural deterioration.