Value of ultrasound examination of the Leeds Enthesitis Index in assessment of disease activity in psoriatic arthritis

Background: Enthesitis is a major feature of psoriatic arthritis. However, clinical assessment of enthesitis is known to lack accuracy and have poor interobserver reliability. Objective: This study aimed to determine the added value of the US assessment of enthesitis according to LEI over the clinical assessment in determination of PsA activity. Methods: A total of 75 consecutive PsA patients diagnosed according to Classification Criteria for Psoriatic Arthritis (CASPAR criteria) participated in the study. The LEI score was used to assess the enthesitis. All PsA patients underwent US assessment by the same sonographer who was blinded to the findings of the clinical examination. Grey scale US imaging was used to assess the longitudinal and transverse planes of the 6 entheseal points of the LEI.