Background: In psoriatic arthritis (PsA), clinical tenderness and ultrasound (US) capture distinct yet related aspects of entheseal disease activity. However, their longitudinal relationship after initiation of biologic disease-modifying antirheumatic drugs (bDMARDs), and the clinical significance of early discordance during follow-up remain unclear. Methods: In this retrospective observational cohort study based on routinely collected medical records, patients with CASPAR-defined PsA and clinically and ultrasonographically active enthesitis at baseline (Clin+/US+) who initiated bDMARD therapy underwent paired, same-day, blinded clinical and US assessments at approximately 6 and 12 months. Agreement between clinical and US findings was quantified using Cohen’s kappa. Discordant states (Clin−/US+ and Clin+/US−) were prespecified, and predictors of Clin−/US+ status at 6 months were analyzed using models that accounted for within-patient clustering. Results: Thirty-nine patients contributed 82 entheses and were treated with either tumour necrosis factor inhibitors (53.8%) or interleukin-17 inhibitors (46.2%). At 6 months, agreement between clinical and US assessments was fair (κ = 0.286; 95% confidence interval [CI], 0.080 to 0.492), with 23.2% of entheses classified as Clin−/US+ and 52.4% as concordantly inactive. At 12 months, agreement improved to substantial-to-almost-perfect levels (κ = 0.779; 95% CI, 0.595 to 0.963), with only 1.2% of entheses remaining Clin−/US+ and 80.5% achieving concordant remission. NSAID exposure was the only significant predictor of Clin−/US+ status at 6 months in univariable analysis (odds ratio [OR], 3.82; 95% CI, 1.27 to 11.47; p = 0.017) and remained associated after multivariable adjustment (OR, 6.16; 95% CI, 1.14 to 33.2; p = 0.03). Conclusions: In PsA patients starting bDMARD therapy, clinical and US assessments of enthesitis showed partial discordance at 6 months, followed by greater convergence at 12 months. These findings suggest that clinical and imaging abnormalities may resolve asynchronously during follow-up and should therefore be interpreted in an integrated, time-aware manner. Residual US abnormalities in the setting of clinical improvement should be interpreted cautiously and within the broader clinical context.

Background/Objectives: Patients with acute anterior uveitis (AAU) have a high prevalence of occult spondyloarthropathy (SpA). Only one previous study investigated ultrasonographic (US) changes at peripheral entheses and joints in patients with acute anterior uveitis (AAU) and no study has used these data in recognizing unknown SpA as defined by ASAS criteria. No previous study compared non-granulomatous (NGAU) with granulomatous uveitis (GAU) for these US features. The objective of this study was to investigate the prevalence of US enthesis and joint abnormalities in a consecutive series of GAU and NGAU patients and to use these data in recognizing unknown SpA as defined by ASAS criteria. Methods: A total of 152 consecutive patients diagnosed with AAU [103 NGAU (42 B27−, 61 B27+) and 49 GAU] from the Immunology Eye Unit (AUSL-IRCCS Reggio Emilia, Italy) were enrolled in this study. Six peripheral entheses as well as knee and ankle joints were bilaterally evaluated by US according to standard methods. The presence of any elementary lesion, structural damage and active enthesitis, according to OMERACT definitions, was recorded. ASAS classification criteria of SpA were integrated with the US data of active enthesitis and joint synovitis in defining the presence of enthesitis and arthritis. Results: NGAU patients had a higher prevalence of entheseal erosions (11.9% vs. 9%, P0 0.009), of enthesis exhibiting a PD signal (29.7% vs. 12.2%, p = 0.025) and of active enthesitis (23% vs. 8.2%, p = 0.026) compared with GAU group. Unknown SpA as defined by ASAS criteria was recognized in 29 patients by clinical and MR/Rx examination of sacroiliac joints and in 13 additional patients with the use of US data. Conclusions: Acute entheseal lesions and erosions are associated with NGAU, without apparent influence of HLA-B27 positivity. US examination helps to recognize previously unknown SpA and to define the disease phenotype of patients, moving toward more personalized treatment.