Psoriatic Arthritis Sonographic Enthesitis Instruments: A Systematic Review of the Literature

As part of the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) ultrasound working group, we performed a systematic review of the literature to assess the evidence and knowledge gaps in scoring instruments of enthesitis in psoriatic arthritis (PsA).

A systematic search of PubMed, EMBase, and Cochrane databases was performed. The search strategy was constructed to find original publications containing terms related to ultrasound, enthesitis, spondyloarthritis (SpA) or PsA. Data extraction focused on the properties of the sonographic enthesitis instruments used in each study following components of the Outcome Measures in Rheumatology (OMERACT) filter: feasibility, test-retest reliability, construct validity as related to clinical assessment of enthesitis, biomarkers of inflammation and imaging of enthesitis by other modalities, discriminative validity, and responsiveness to treatment.

Fifty-one of 310 identified manuscripts were included. Only 1 scoring instrument of enthesitis was specifically developed and validated in patients with PsA. Only 18 (35%) of the studies involved patients with PsA, while the remaining studies focused on SpA. In PsA, construct validity was assessed using biomarkers and clinical examination in 1 (2%) and 11 (21.5%) of the studies, respectively, whereas no studies used imaging for the same purpose. Only 2 (4%) of the studies assessed discriminative validity in PsA. Responsiveness to treatment was assessed in 7 studies, none of which included patients with PsA.

Although sonographic enthesitis scoring instruments have been developed for SpA, only a few have been validated in PsA. None of them passed the OMERACT filter in patients with PsA. Additional research is required before endorsing a specific instrument for the assessment of enthesitis in patients with PsA.