SAT0304 Preclinical phases of psoriatic arthritis: a cross-sectional ultrasonographic study on psoriasis and psoriatic arthralgia patients

Background Identify the preclinical phase of arthritis could be clinically relevant. In this scenario, musculoskeletal ultrasonography (US) may play an important role, since it may detect subclinical disease. Psoriatic Arthritis (PsA) is a perfect disease to identify risk factors, since the risk pool group [i.e. patients with only cutaneous Psoriasis (Pso)] is known. Objectives To evaluate in Pso patients, with and without clinical arthralgia (CA), defined by the presence of joint pain without other clinical evidence of musculoskeletal inflammation: I) the prevalence of subclinical US inflammation in joints, enthesis, tendons and bursae; II) the prevalence of US structural damage; III) the relationship between US lesions and clinical data. Methods Cross-sectional prevalence study of US abnormalities in Pso patients with or without CA and healthy controls (HCs). Inclusion and exclusion criteria (e.g. osteoarthritis and fibromyalgia) are pre-defined. Forty-four joints (MCP, PIP and DIP joints, wrists, knees, MTP joints) and 12 enthesis (achilles, quadriceps, proximal and distal patellar, plantar aponeurosis and common extensor tendon enthesis) were scanned in each patient. US scans were performed using a ESAOTE MyLabClassC equipped with a high frequency linear probe. Active synovitis was defined by the presence of a grade ≥2 for grey scale (GS) and ≥1 for PD, while active enthesitis if there was hypoecogenity in GS and an entheseal PD signal (≤2 mm from bone insertion). Results Sixty-four Pso patients and 21 HCs were included; globally 2816 joints and 768 entheses were scanned. Twenty-three out of 64 (35.9%) Pso patients displayed CA. Baseline characteristics are reported in table 1. Active synovitis was found, in at least one joint, in 20/64 (31.3%) Pso patients and 0/21 HCs (p=0.002), while active enthesitis in 14/64 (21.9%) Pso patients and 0/21 HCs (p=0.017). No significant differences were found for active synovitis or enthesitis between the two subgroups of Pso, with or without CA. In the Pso cohort, 5/23 (23.8%) patients with CA and 2/41 (5%) without CA displayed tenosynovitis or paratenonitis (p=0.042). Furthermore, active synovitis, as well as GS-synovitis ≥2, was associated with higher NAPSI (9.7±8.0 vs 4.6±7.1, p=0.04 for GS ≥2), whereas active enthesitis was associated with higher PASI (5.4±3.0 vs 3.7±2.9, p=0.02). No significant differences were found between Pso patients and HCs for the structural damage (i.e. osteoproliferation and erosions), both for joints and enthesis. Conclusions In Psoriasis subclinical US active synovitis and/or enthesitis are present in 20%–30% of patients. In Pso the comparison between groups, with or without CA, show no significant difference in active subclinical synovitis or enthesitis, but Pso patients with CA present more frequently US tenosynovitis or paratenonitis. In Pso subclinical US synovitis or enthesitis are significantly associated with higher NAPSI and PASI. The relevance of these results, to possibly identify a subgroup of Pso more prone to develop PsA, deserve further investigation and prospective evaluation. Disclosure of Interest None declared