Study Identifies Most Discriminative Ultrasound Lesions for Spondyloarthritis

The most discriminative Outcome Measures in Rheumatology (OMERACT) ultrasound lesions for spondyloarthritis (SpA) are power Doppler (PD) signals at the enthesis and bone erosions, according to a study published in Annals of the Rheumatic Diseases.

“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,” wrote corresponding author Andrea Di Matteo, MD, PhD, of Polytechnic University of Marche, Ancona, Italy, and study coauthors.

The study included 413 patients with SpA, including axial SpA and psoriatic arthritis, and 282 control subjects with osteoarthritis and fibromyalgia from a total 20 rheumatology centers. Patients underwent clinical examinations and ultrasound of lower limb large entheses. PD at the enthesis grade ≥1 plus entheseal thickening and/or hypoechoic areas, and PD grade >1 independent of entheseal thickening or hypoechoic areas, were considered active enthesitis.

Enthesophytes/calcifications aside, all OMERACT lesions were significantly associated with SpA in the univariate analysis, according to the study. In multivariate analysis, PD and bone erosions retained the association. Researchers reported odds ratios of 8.77 with PD and 4.75 with bone erosions.

With a 1.93 odds ratio, the Achilles tendon was the only lower limb enthesis significantly linked with SpA in multivariate analysis.

The study also found a significant association between active enthesitis and SpA: researchers reported a 9.20 odds ratio. Moreover, in regression analysis active enthesitis was consistently linked with most clinical measures of SpA disease activity and severity. Individual OMERACT ultrasound lesions were not.

“Ultrasound could differentiate between SpA-related enthesitis and other forms of entheseal pathology (ie, mechanical enthesitis),” researchers wrote, “thus improving the assessment of entheseal involvement in SpA.”

Reference

Di Matteo A, Smerilli G, Di Donato S, et al. 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. Ann Rheum Dis. 2024;83(7):847-857. doi:10.1136/ard-2023-225443