SAT0401 SWOLLEN JOINTS ARE ASSOCIATED WITH ULTRASOUND POWER DOPPLER SYNOVITIS, WHEREAS TENDER JOINTS IN THE ABSENCE OF SWELLING ARE NOT: AN ANALYSIS OF AGREEMENT AND CORRELATION IN VERY EARLY DMARD NAÏVE PSORIATIC ARTHRITIS
Authors: S. Dubash, O. Alabas, X. Michelena, L. Garcia-Montoya, G. De Marco, M. Merashli, R. Wakefield, P. Helliwell, D. Mcgonagle, A. L. Tan, P. Emery, H. Marzo-Ortega
Journal: Annals of the Rheumatic Diseases (2020)

Background: Ultrasound (US) is an imaging adjunct to clinical joint examination adding sensitivity and objectivity to the assessment of inflammation. Previous studies in PsA have shown disparity between ultrasound and clinical findings with significant subclinical joint inflammation. A clinical challenge in PsA is to interpret tender joints (TJ) that are not swollen (SJ). As US is not widely used, alignment of clinical with US assessment is needed to determine its future role. Objectives: To determine how joint clinical examination relates to US findings in very early DMARD naïve PsA. Methods: Newly diagnosed DMARD naïve PsA patients, fulfilling CASPAR criteria, were recruited into the Leeds Spondyloarthropathy Register for Research and Observation (SpARRO), a prospective observational cohort study. US examination of 48 joints per patient was conducted by trained ultra-sonographers, blinded to clinical details with semi-quantitative scoring (0-3) for gray scale (GS) and power Doppler (PD). TJ and SJ counts were independently recorded. Cross-sectional baseline analysis was performed. The prevalence-adjusted and bias-adjusted kappa (PABAK) was calculated to determine agreements between clinical and US parameters. Spearman’s rank correlation coefficient was calculated to identify permutations of TJ/SJ correlating with GS ≥2, PD≥1 or both. Results: A total 5927 joints were scanned in 155 PsA patients. The mean age was 44.4 years, (SD 12.8), median disease duration 5.1 weeks (0.4-13.1); median TJC=7 (3-14) and SJC=2 (1-7). Oligoarthritis was present in 63.9% (99/155). US GS≥2 was frequently detected in the feet at MTPs1-4 (37.4- 53.6 %) and wrists (26.5- 33.6%). PD was most prevalent at wrists (17.5%) and MTP1 (12.6%) but observed less in other joints. Erosions were less frequent, the commonest site being MTP5 (17/310, 5.4%). Overall, SJ demonstrated high agreement (p&lt;0.001) with US synovitis (GS ≥2 and/or PD ≥1). High agreement was equivalent between combined GS ≥2 and PD ≥1 compared with PD ≥1 alone (p&lt;0.001) indicating it was predominantly driven by PD. Agreement with TJ and US was consistently lower yet still significant (p&lt;0.001). Combinations of TJ/SJ were explored with US synovitis (table 1). Correlation was significant for T+ S+ and PD≥1 at wrists, MCP1-5, PIP2-5, MCP3-4 (p&lt;0.001); DIP2 (p&lt;0.05), knees and ankles (p&lt;0.01) but weaker correlation in MTP3,4. In contrast, poor correlation was observed in the T+ S- group for most joints. Table 1. Agreement between TJ or SJ with GS≥2 &amp; PD ≥1 and correlations for tender with/ without swollen combinations for right sided hand/feet joints. Tender Swollen T+ S- T+ S+ Joint (Right ) A (%) PABAK A (%) PABAK r r Wrist 75.5 0.51* 89.1 0.78* -0.09 0.35* MCP1 84.1 0.68* 87.5 0.75* 0.09 0.44* MCP2 77.7 0.55* 83.1 0.66* 0.08 0.35* MCP3 79.1 0.58* 84.5 0.69* 0.005 0.50* MCP4 78.4 0.57* 86.4 0.72* 0.07 0.22† MCP5 87.8 0.76* 95.6 0.91* -0.03 0.49* MTP1 69.8 0.40* 83.9 0.68* -0.03 - MTP2 79.1 0.58* 90.5 0.81* 0.06 0.11 MTP3 77.0 0.54* 88.5 0.77* 0.05 0.22‡ MTP4 77.7 0.55* 87.2 0.74* -0.002 0.23‡ MTP5 79.9 0.60* 89.9 0.80* 0.15 0.09 T+= tender, S+ =swollen, S- = not swollen, A=agreement (%), r =coefficient, † p&lt;0.05, ‡ p&lt;0.01, *p&lt;0.001. Conclusion: Swollen joints demonstrate higher agreement with US synovitis (PD≥1 alone or GS ≥2 &amp; PD ≥1 combined) than tender joints in early PsA. In addition, joints that are tender but not swollen have poor correlation with US synovitis at the individual joint level indicating that swelling is a better clinical discriminator of active synovitis, and factors other than synovial inflammation may drive tenderness in very early, DMARD naïve PsA. These results suggest re-appraisal of clinical joint counts is needed to refine treatment decision making in early PsA. Disclosure of Interests: Sayam Dubash: None declared, Oras Alabas: None declared, Xabier Michelena: None declared, Leticia Garcia-Montoya: None declared, Gabriele De Marco: None declared, Mira Merashli: None declared, Richard Wakefield Speakers bureau: Novartis, Janssen, GE, Philip Helliwell: None declared, Dennis McGonagle Grant/research support from: Janssen Research &amp; Development, LLC, Ai Lyn Tan: None declared, Paul Emery Grant/research support from: AbbVie, Bristol-Myers Squibb, Merck Sharp &amp; Dohme, Pfizer, Roche (all paid to employer), Consultant of: AbbVie (consultant, clinical trials, advisor), Bristol-Myers Squibb (consultant, clinical trials, advisor), Lilly (clinical trials, advisor), Merck Sharp &amp; Dohme (consultant, clinical trials, advisor), Novartis (consultant, clinical trials, advisor), Pfizer (consultant, clinical trials, advisor), Roche (consultant, clinical trials, advisor), Samsung (clinical trials, advisor), Sandoz (clinical trials, advisor), UCB (consultant, clinical trials, advisor), Helena Marzo-Ortega Grant/research support from: Janssen, Novartis, Consultant of: Abbvie, Celgene, Eli Lilly, Janssen, Novartis, Pfizer, UCB, Speakers bureau: Abbvie, Celgene, Eli Lilly, Janssen, Novartis, Pfizer, Takeda, UCB