Background The use of ultrasonography (US) in RA is rapidly increasing. Currently, there is no consensus regarding which joints should be systematically assessed. The comprehensiveness of joint examination as well as validity and responsiveness must be weighted against feasibility.

Objectives To explore and validate different US joint scores of inflammation compared to a comprehensive US assessment in patients with early and established RA.

Methods 230 DMARD naïve patients with early RA (according to 2010 ACR/EULAR criteria) with indication for methotrexate, and 212 patients with established RA with indication for biologic DMARDs were examined between January 2010 and June 2013. An extensive US examination was performed by experienced sonographers using a validated grey-scale (GS) and power Doppler (PD) semi-quantitative scoring system with ranges 0-3 for GS and PD in each of the following 36 joints: MCP 1-5, PIP 2-3, radiocarpal, distal radioulnar, intercarpal, elbow, knee, talocrural and MTP 1-5 bilaterally. An US atlas was used as reference¹. Previously published 32-¹, 12-², 7-³ and 6-⁴ joint scores as well as a new 30-joint score were assessed. This 30-joint score was based on the 36 examined joints with exclusion of the 6 largest joints (elbow, knee and talocrural bilaterally), due to low prevalence of US PD findings and improved feasibility (shorter examination time (≤10 min) and no need to remove patient's clothes). We estimated % coverage (with 95% CI) of each of the reduced joint scores to estimate the proportion of patients with inflammatory findings compared to the 36-joint score.

Results A total of 442 patients were included, 230 with early and 212 with established RA; 81.5% vs 82.0% were anti-CCP positive, mean (SD) age was 51 (14) vs 58 (12) years, DAS28 4.7 (1.2) vs 4.8 (1.4), median (25-75 percentile) 28-swollen joint count 6 (3-11) vs 5 (2-10), CRP mg/L 7 (3-18) vs 8 (3-22), disease duration 0.5 (0.2-0.9) vs 7 (3 -11) years. The mean (95% CI) 36-joint US GS score was 23 (21-25) vs 28 (25-30) (p=0.003) and the 36-joint US PD score 11 (10-12) vs 13 (11-15) (p=0.2) in the early vs established RA cohort.

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Conclusions Reduced joint scores of 12, 7 or 6 joints seem to be suitable for detecting most of the inflammatory pathology in established RA. However, the loss in sensitivity to detect patients with pathological findings was more pronounced in early RA, and a more comprehensive assessment may be warranted to improve coverage of affected joints. A novel 30-joint score that is feasible (time to score US GS and PD in both hands and feet takes ≤10 min), might improve sensitivity.

References

1. Rheum Dis 2011 70:11 1995-8.

2. Clin Exp Rheumatol 2005;23:881-4.

3. Arthritis Rheum 2009;61:1194-201.

4. Rheumatology 2012;51:866-873.

Disclosure of Interest A.-B. Aga: None declared, H. B. Hammer Grant/research support: AbbVie, Roche, Pfizer, E. Lie: None declared, I. C. Olsen: None declared, T. Uhlig: None declared, D. van der Heijde: None declared, T. K. Kvien Grant/research support: AbbVie, BMS, MSD/Schering-Plough, Pfizer/Wyeth, Roche, UCB, Consultant for: AbbVie, BMS, Celltrion, Eli Lilly, Hospira, MSD/Schering-Plough, Orion Pharma, Pfizer/Wyeth, Roche, UCB, E. A. Haavardsholm Grant/research support: AbbVie, Pfizer, MSD, Roche, UCB

DOI 10.1136/annrheumdis-2014-eular.2750