Background It has been shown that patients in remission of rheumatoid arthritis (RA) continue to have subclinical synovitis1.
Objectives To evaluate the usefulness of the US7 scoring system in detecting synovitis in patients with RA who are in remission of disease.
Methods 73 patients with remission of rheumatoid arthritis (RA) according to DAS 28 <2.6 criteria with duration of at least 3 months were identified. ACR/EULAR remission criteria were assessed separately. HAQ, SJC, and TJC were evaluated during 1 year at 3 months intervals. The 7-joint ultrasound score (US7) was used for all US assessments2. Sonographers used the same US machine; settings were not allowed to be changed. Inter- and intraobserver reliability in using US7 scoring system were computed for all measurements. Spearmann coefficient was used to calculate statistical correlations.
Results 212 patient visits were recorded and 1484 joints were investigated. Only 13 patients (17.3%) in clinical remission had no synovitis in US7 (GS0, PD0), regardless whether tenosynovitis was present or not. 50 patients (68%) continued to have subclinical synovitis in US7 at the baseline (GSUS/PDUS>1). Relapse rate during one-year observation (DAS28>2.6) was 17% at 3rd and 6th months, respectively, 11% in 9th month and 18% at 12th month, respectively. Total score of GSUS and PDUS synovitis at month 3 (p<0,01, p<0,05) and 6 (p<0,001, p<0,01) correlated well with DAS 28 score. This statistical significance was not reached in month 1 and 9, where the relapse rate was 0 (baseline) and low (month 9), thus only subclinical synovitis was more frequently seen while DAS28<2.6. GSUS synovitis on US7 significantly correlated with ACR/EULAR remission criteria at months 1,3,6 and 12 (all p<0,01). There was a strong correlation between present synovitis and tenosynovitis on US7 but no correlation of TS itself and other disease activity or disability parameters were observed (HAQ, DAS28, ACR remission crit.). Number of erosions increased during one-year observation.
Conclusions With the US7 score, it was possible to find a high percentage of subclinical synovitis in patients in remission of RA according to previous studies published using other scoring systems. Therefore, US7 might be a simple and effective tool to monitor disease activity of RA even in the state of remission. There was a better correlation between US7 GSUS findings and ACR/EULAR remission criteria than remission assessed according to DAS28 criteria. Further studies are needed to confirm these findings with US7 scoring system.
Gärtner M, et al. Sonographic joint assessment in rheumatoid arthritis: associations with clinical joint assessment during a state of remission. Arthritis Rheum. 2013 Aug;65(8):2005-14.
Backhaus TM, et al. The US7 score is sensitive to change in a large cohort of patients with rheumatoid arthritis over 12 months of therapy. Ann Rheum Dis. 2013 Jul;72(7):1163-9.
Acknowledgements Supported by project of MHCR for conceptual development of research organization 023728 and IGA grant No. NT12437.
Disclosure of Interest None declared