Background/Purpose: Musculoskeletal ultrasonography (US) is one of the standard tools for the diagnosis and monitoring of rheumatoid arthritis (RA). Although we and other groups have proposed several sets of US assessment procedures in arbitrary combinations of selected joints, there is still no consensus in defining the joints to evaluate. Here, we investigated whether US assessment in the selected 8 joints which we have advocated as a routine assessment for detecting RA synovitis is also useful for monitoring response to treatment for RA.

Methods: Power Doppler (PD) US was performed in 24 joints, including all PIP, MCP, bilateral wrist and knee joints, as comprehensive evaluation in 15 RA patients treated with certolizumab pegol (CZP). Before and after treatment with CZP, PD signals and gray-scale (GS) images were scored semiquantitatively from 0 to 3 in each joint. Total PD score-24 and total PD score-8 were calculated by summing up PD scores of the 24 joints and the selected 8 joints (bilateral second and third MCP, wrist, and knee joints), respectively. Total GS score-24 and total GS score-8 were also calculated by summing up GS scores of the 24 joints and the selected 8 joints, respectively.

Results: Change amount of total PD score-8 by treatment with CZP exhibited strong correlations with the changes of disease activity indices, SDAI (r_s = 0.92, p < 0.01) and DAS28-CRP (r_s = 0.89, p < 0.01). Change amount of total PD score-24 also correlated strongly with the changes of SDAI (r_s = 0.91, p < 0.01) and DAS28-CRP (r_s = 0.86, p < 0.01), and the correlation coefficients were comparable with those for total PD score-8. Although the change of total PD score-8 correlated well with the changes of some components of disease activity indices, including swollen joint count (r_s = 0.81, p < 0.01), tender joint count (r_s = 0.91, p < 0.01), CRP (r_s = 0.82, p < 0.01) and ESR (r_s = 0.63, p < 0.01), there were no significant correlations between the changes of total PD score-8 and the changes of patient’s global assessment (r_s = 0.39, p > 0.05) and evaluator’s global assessment (r_s = 0.22, p > 0.05). The change of total PD score-24 correlated more weakly with the changes of swollen joint count (r_s = 0.74, p < 0.01) and tender joint count (r_s = 0.86, p < 0.01) as compared to total PD score-8. The correlation coefficients between the change of total PD score-24 and the changes of CRP (r_s = 0.85, p < 0.01) and ESR (r_s = 0.62, p < 0.01) were comparable with those for total PD score-8. There were no significant correlations between the changes of total PD score-24 and the changes of patient’s global assessment (r_s = 0.42, p > 0.05) and evaluator’s global assessment (r_s = 0.27, p > 0.05). The changes of total GS score-8 and total GS score-24 correlated to the changes of SDAI with the same level of correlation coefficients (r_s = 0.69, p < 0.01, and r_s = 0.70, p < 0.01).

Conclusion: This study indicates that the change of the 8-joint US scores by treatment correlated with the changes of disease activity indices as strongly as the change of the comprehensive 24-joint scores. Thus the 8-joint assessment can be a useful method for monitoring response to treatment in RA patients.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-8-joint-ultrasound-score-is-a-useful-marker-for-monitoring-therapeutic-response-in-rheumatoid-arthritis/