Monitoring anti-TNFα treatment in rheumatoid arthritis: responsiveness of magnetic resonance imaging and ultrasonography of the dominant wrist joint compared with conventional measures of disease activity and structural damage

Objectives: To evaluate the responsiveness of magnetic resonance imaging (MRI) and ultrasonography (US) compared with conventional measures of disease activity and structural damage in patients with rheumatoid arthritis (RA) during the first year of treatment with antitumour necrosis factor alpha (TNF alpha). Methods: A cohort of patients with RA (N=36, median age 53 years, disease duration 7.6 years and disease activity score (DAS28) 5.7) was evaluated by core measures of disease activity, US (one wrist), MRI (one wrist) and conventional radiography (CR, both hands and wrists) at initiation of treatment with anti-TNF alpha agents and after 3, 6 and 12 months. Responsiveness was assessed by standardised response means (SRM). Accepted thresholds were applied to classify responsiveness as trivial, low, moderate or good. Results: MRI synovitis (SRM between 20.79 and 20.92) and the MRI total inflammation score comprising synovitis, tenosynovitis and bone marrow oedema (SRM between 21.05 and 21.24) were highly responsive. Moderate to high responsiveness was found for MRI tenosynovitis and bone marrow oedema, all the composite indices (DAS28, simplified disease activity index (SDAI) and clinical disease activity index (CDAI)) and the 28-swollen joint count. US displayed low to moderate responsiveness. The MRI erosion score displayed low responsiveness but was more responsive than CR measures at 3 and 6 months follow-up. MRI and CR measures of annual progression rates of damage performed similarly and were highly responsive. Conclusions: The most responsive measure of inflammation when evaluating anti-TNF alpha medication was a composite measure comprising MRI synovitis, tenosynovitis and bone marrow oedema, and this may be a promising outcome measure in clinical studies.