Power Doppler signal at the enthesis and bone erosions are the most discriminative OMERACT ultrasound lesions for SpA: results from the DEUS (Defining Enthesitis on Ultrasound in Spondyloarthritis) multicentre study.

OBJECTIVES: To assess, in spondyloarthritis (SpA), the discriminative value of the Outcome Measures in Rheumatology (OMERACT) ultrasound lesions of enthesitis and their associations with clinical features in this population. METHODS: In this multicentre study involving 20 rheumatology centres, clinical and ultrasound examinations of the lower limb large entheses were performed in 413 patients with SpA (axial SpA and psoriatic arthritis) and 282 disease controls (osteoarthritis and fibromyalgia). 'Active enthesitis' was defined as (1) power Doppler (PD) at the enthesis grade ≥1 plus entheseal thickening and/or hypoechoic areas, or (2) PD grade >1 (independent of the presence of entheseal thickening and/or hypoechoic areas). RESULTS: In the univariate analysis, all OMERACT lesions except enthesophytes/calcifications showed a significant association with SpA. PD (OR=8.77, 95% CI 4.40 to 19.20, p<0.001) and bone erosions (OR=4.75, 95% CI 2.43 to 10.10, p<0.001) retained this association in the multivariate analysis. Among the lower limb entheses, only the Achilles tendon was significantly associated with SpA (OR=1.93, 95% CI 1.30 to 2.88, p<0.001) in the multivariate analyses. Active enthesitis showed a significant association with SpA (OR=9.20, 95% CI 4.21 to 23.20, p<0.001), and unlike the individual OMERACT ultrasound lesions it was consistently associated with most clinical measures of SpA disease activity and severity in the regression analyses. CONCLUSIONS: This large multicentre study assessed the value of different ultrasound findings of enthesitis in SpA, identifying the most discriminative ultrasound lesions and entheseal sites for SpA. Ultrasound could differentiate between SpA-related enthesitis and other forms of entheseal pathology (ie, mechanical enthesitis), thus improving the assessment of entheseal involvement in SpA.

The relationship between ultrasound and physical examination in the assessment of enthesitis in SpA patients: results from the DEUS multicentre study: The role of ultrasound and physical examination in assessing enthesitis in SpA patients.

OBJECTIVES: i) To explore the agreement between the OMERACT ultrasound lesions of enthesitis and physical examination in assessing enthesitis in spondyloarthritis (SpA) patients; ii) To investigate the prevalence and clinical relevance of subclinical enthesitis in this population. METHODS: Twenty rheumatology centres participated in this cross-sectional study. SpA patients, including axial SpA (axSpA) and psoriatic arthritis (PsA) patients, underwent both ultrasound scan and physical examination of large lower limb entheses. The OMERACT ultrasound lesions of enthesitis were considered, along with a recently proposed definition for 'active enthesitis' by our group. Subclinical enthesitis was defined as the presence of 'active enthesitis' in ≥1 enthesis in SpA patients without clinical enthesitis (i.e., number of positive entheses on physical examination and Leeds Enthesitis Index score =0). RESULTS: 4130 entheses in 413 SpA patients (224 axSpA/189 PsA) were evaluated through ultrasound and physical examination. Agreement between ultrasound and physical examination ranged from moderate (i.e., enthesophytes) to almost perfect (i.e., power Doppler and 'active enthesitis'). Patellar tendon entheses demonstrated the highest agreement, whereas Achilles tendon insertion showed the lowest. Among 158/413 (38.3%) SpA patients with clinical enthesitis, 108 (68.4%) exhibited no 'active enthesitis' on ultrasound. Conversely, of those 255 without clinical enthesitis, 39 (15.3%) showed subclinical enthesitis. Subclinical enthesitis was strongly associated with local structural damage. However, no differences were observed regarding the demographic and clinical profiles of SpA patients with and without subclinical enthesitis. CONCLUSIONS: Our study underscores the need for a comprehensive tool integrating ultrasound and physical examination for assessing enthesitis in SpA patients.