AB0185 ULTRASOUND IN INFLAMMATORY ARTHRALGIA: SHOULD WE ALWAYS SCAN?
Authors: K. López Gloria, I. Castrejon, J. C. Nieto González, J. Rivera, J. Martínez-Barrio, B. Serrano-Benavente, L. Trives Folguera, J. M. Alvaro-Gracia, J. Molina Collada
Journal: Annals of the Rheumatic Diseases (2021)

Background: Patients with inflammatory arthralgia (IA) are considered to be at increased risk for progression to RA. Ultrasound (US) has shown high sensitivity to detect synovitis compared with physical examination. Thus, US is recommended to identify subclinical synovitis in patients without clinical signs of inflammation. Objectives: To determine the frequency and pattern of US detected active inflammation in patients with IA and investigate factors contributing to predict this outcome. Methods: An US clinic is scheduled in an academic center running twice every week. A retrospective analysis of our US unit cohort during a period of 12 months was undertaken. Patients with IA and no previous diagnosis of inflammatory arthropathies were included for analysis. Inclusion criteria of IA definition included: severe symptoms presenting in the morning, duration of morning stiffness ≥60 min, symptoms predominantly located in MCP joints and absence of clinically detected synovitis by the referral rheumatologist. The following routinely collected variables were included in the analysis: demographics, clinical features and laboratory tests. Patients underwent bilateral US examination of hands and/or feet according to the European League Against Rheumatism (EULAR) guidelines. The presence of synovitis and tenosynovitis was assessed on a semi quantitative scale (0–3) for Grey Scale(GS)/Power Doppler(PD). Active inflammation was defined as PD synovitis and/or tenosynovitis &gt;1 at any location. First, differences between groups were tested using chi-squared/Fisher and Student-t tests in the univariate analysis. Second, multivariate logistic regression models were employed to investigate the association between possible predictive factors of US active inflammation. Results: A total of 110 patients were included in the analysis. Mean age was 53.6±15.6 years, 80 (72.7%) were females, and mean symptoms duration was 11.7±9.9 months (Table1). A total of 76 (69.1%) patients presented with a polyarticular arthralgia pattern. US active inflammation were present in 38 (34.5%) patients (28.2% showed PD synovitis and 19.1% PD tenosynovitis). Hands were most commonly involved with PD synovitis at wrists in 18.2% and at MCP in 14.5% of patients. For PD tenosynovitis, the flexor MCP 2-5 (4.5%) and 6 th extensor tenosynovitis (5.5 %) were the most frequent affected locations. Only 9 (8.2%) patients had erosions in hands and/or feet at baseline examination. In the univariate analysis, the higher ESR values, the shorter time from symptoms onset and the presence of ACPA were significantly associated with the presence of US active inflammation (p&lt;0.001, p=0.035 and p=0.01, respectively). In the multivariate analysis, only ACPA and ESR values (OR=1,0003; 95%CI 1,000-1,006 and OR=1.054; 95%CI 1.016-1.094), remained significantly associated with the detection of US active inflammation. Conclusion: US features of active inflammation are found in 1 over 3 patients with IA being PD synovitis the most common finding, specially at the wrists and MCP joints. Higher ESR and ACPA values are significantly associated with the presence of US active inflammation. Thus, we strongly recommend the use of PD US to detect subclinical inflammation in at-risk patients with IA with no sign of inflammation on clinical examination, especially those with high ESR and ACPA values. Table 1. Baseline characteristics of patients with IA Total n= 110 US inflammatory findings n= 38 (34.5%) Non-US inflammatory findings n=72 (65.5%) p Age 53.6 ± 15.6 57.2±16.2 51.6±13.4 0.071 Sex Female 80 (72.7%) 26 (68.4%) 54 (75%) 0.461 Smoking n= 87 Non smoker 45 (51.7%) 12 (44.4%) 33 (55%) 0.412 Smoker 34 (39.1%) 11 (40.7%) 23 (38.3%) Former smoker 8 (9.2%) 4 (14.8%) 4 (6.7%) Extension Monoarticular 12 (10.9%) 6 (15.8%) 6 (8.3%) 0.176 Oligoarticular 22 (20%) 10 (26.3%) 12 (16.7%) Polyarticular 76 (69.1%) 22 (57.9%) 54 (75%) Time (months) from symptoms onset 11.7 ± 9.9 9.1±8.1 13±10.5 0.035 ESR (mm/h) n=45 24.7 ± 18.2 33.1±21.8 20.3 ±14.4 &lt;0.001 RF (IU/mL) n=53 39.1 ± 230.5 28.5±56 45.1±286.1 0.647 ACPA (IU/mL) n=56 98.1 ± 331.2 209.4±488.4 26±125.2 0.01 Disclosure of Interests: None declared