Background/Purpose: Ultrasound has become a routinely available bedside method for the evaluation of patients with Rheumatoid Arthritis (RA). However, it is time consuming, making it difficult to use in daily clinical practice. The aim of our study was to develop a new standardized ultrasound score including only 6 joints that could be applied to daily monitoring disease activity in patients with RA.

Methods: We included RA patients (American College of Rheumatology 1987 criteria). Each patient underwent clinical, radiological and ultrasonographic (US) evaluation. Clinical data included 28-joints count and disease activity index 28 (DAS28). Ultrasound evaluation was performed by two rheumatologists who were blind to clinical examination. Six joints were evaluated: bilateral wrist (dorsal view of radio and intracarpal joint), second metacarpophalangeal (2MCP; dorsal and palmar view), and fifth metatarsophalangeal (5MTP; dorsal view). US synovitis was defined as a gray scale (GS) score ≥1. Synovial vascularity was assessed by power Doppler (PD) and graded from 0 to 3, according to OMERACT standards. The US score comes from the addition of the presence of synovitis (one point) and the degree PD, with a total score ranged from 0 to 40 (synovitis subscale = 0–10; PD subscale = 0–30). Final score was correlated with clinical variables (Spearman’s rho) and stratified according to patients’ disease activity (Kruskal Wallis and post-hoc tests).  

Results: 124 patients were included. Mean age was 53 ± 13 years, 86% were female, and disease duration was 9.4 ± 8.5 years. Tender and swollen joints count were 3.3 ± 4 and 3.5 ± 4.5, respectively. DAS28 score was 3.8 ± 1.4. A total of 744 joints were evaluated. 548 (74%) exhibited ultrasonographic changes (PD ≥1 = 35%; synovitis = 69%). 2MCP and 5MTP showed erosions in 70% and 83%, respectively.  Mean ultrasonographic score was 11.4 ± 6.5 (Doppler subscale 4.8 ± 6.5; Synovitis subscale 6.6 ± 2.2). The score had a moderate correlation with swollen joint count and DAS28 (Spearman´s rho 0.60 and 0.54, respectively; p<0.001). The score was able to discriminate patients with high disease activity from those with moderate, low activity and remission (Remission= 8 ± 4, low activity= 9 ± 5, Moderate activity= 11 ± 5, High activity= 19 ± 8; p<0.01).  Excluding the 5MTP and synovitis subscale did not affect the results, showing an excellent correlation with primary score (Spearman’s rho 0.98 and 0.96, respectively; p<0.001). US examination was fast, taking 8 minutes per patient, including documentation. 

Conclusion: A reduced US score of 6 joints showed to be fast and a valid tool to detect and monitor disease activity in patients with RA. Ultrasonographic assessment of bilateral wrist, second MCP and fifth MTF could be enough for evaluating overall inflammatory activity, reducing the examination time, thereby making it possible to integrate the ultrasound to the daily rheumatologic practice.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/development-of-a-6-joint-simplified-ultrasonographic-score-to-assess-disease-activity-in-patients-with-rheumatoid-arthritis/