Ultrasonography predicts achievement of Boolean remission after DAS28-based clinical remission of rheumatoid arthritis

Abstract

Objectives. To determine whether ultrasonography (US) predicts Boolean remission in rheumatoid arthritis (RA) patients who had achieved disease activity score in 28 joints (DAS28)-based remission criteria.

Methods. Thirty-one RA patients in DAS28-based clinical remission were recruited. US semiquantitatively determined Gray scale (GS) and power Doppler (PD) signal scores in the bilateral wrists and all metacarpophalangeals and proximal interphalangeals. Total GS score and total PD score were calculated as the sum of individual scores for each joint.

Results. Among 22 RA patients, who maintained DAS28 remission for 2 years, 16 met Boolean remission criteria at the end of study. Both total GS and total PD scores at baseline were significantly lower in Boolean remission group than non-remission group. There was no significant difference in other baseline parameters, including duration of disease, duration of remission, mTSS, and disease activity composite parameters between the two groups. Among the factors for Boolean remission criteria at 2 years, patient global assessment score was associated with total GS score at the entry, while swollen joint count was related to total PD score.

Conclusions. Null or low grade of GS and PD findings in US are associated with achieving Boolean remission. Thus, US is essential for assessment and prediction of “deeper remission” of RA.

Keywords:

• Boolean remission
• Clinical remission
• Power Doppler
• Rheumatoid arthritis
• Ultrasonography

Acknowledgments

We thank all the colleagues in our laboratories for kind cooperation in this project. We also thank Mr. Tom Kiper for his review of the manuscript.

Funding

This work was supported by the Naito Foundation (R. Y.) and the Japan Rheumatism Foundation (R. Y.).

Conflict of interest

None.