Psoriatic Arthritis Damage Marked by Enthesitis Severity

Sonographic enthesitis severity is a potential marker of radiographic peripheral and axial joint damage in psoriatic arthritis, a study showed.

Researchers conducted a cross-sectional analysis to examine the association between sonographic enthesitis and the severity of radiographic features of damage in the peripheral and axial joints in patients with psoriatic arthritis.

They used the MAdrid Sonography Enthesitis Index (MASEI) scoring system to quantify the extent of sonographic entheseal abnormalities.

Radiographic damage in the peripheral joints and spine was assessed by the modified Steinbrocker score (mSS), the Modified New York Criteria for sacroiliitis, and the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS).

The association between MASEI and the extent of radiographic damage was assessed with negative binomial and logistic regression.

Some findings:

• Clinical enthesitis was found in 13.9% of the 223 patients included in the analysis.

• The mean MASEI score was 15.6 ± 12.6; the mean mSS was 18.7 ± 33.6. With respect to axial radiographic damage, the mean mSASSS was 1.7 ± 7.2 and 37.1% of the patients had sacroiliitis.

• Regression analyses yielded an association between higher MASEI scores (10 units increase) and peripheral joint damage, including mSS, joint ankylosis, arthritis mutilans, and periostitis.

• An association was found between higher MASEI scores and axial damage as measured by mSASSS and sacroiliitis.

The agreement between sonographic and clinical assessment of enthesitis is an area of interest in rheumatology because of the limited specificity and sensitivity of the latter method, the authors noted.

“To our knowledge, this is the largest study thus far that explored the association between sonographic enthesitis and radiographic joint damage in PsA,” they said. “The use of sonographic enthesitis as a primary predictor improved the accuracy of assessing this important feature over physical examination.”

The findings raise the question of whether enthesitis has a role in the pathogenesis of articular damage in psoriatic arthritis, the authors added. “Further longitudinal studies in early PsA patients are required in order to establish the precise cause and effect relationships between enthesitis, synovitis, and joint damage.”

The researchers reported their findings in Arthritis Research & Therapy.

References:

Polachek A, Cook R, Chandran V, et al. “The association between sonographic enthesitis and radiographic damage in psoriatic arthritis.” Arthritis Res Ther. 2017;19:189. doi: 10.1186/s13075-017-1399-5.