SAT0212 Can We Use Enthesis Ultrasound as an Outcome Measure of Disease Activity in Spondyloarthritis? A Study at Achilles Level

Background Spondyloarthritis (SpA) is a group of disorders that are characterized by inflammatory involvement of the enthesis and the adjacent bone. Enthesitis is regarded as the primary lesion and is observed in all SpA subtypes, and may sometimes be present for several years as an isolated clinical manifestation. Ultrasound is currently considered a powerful tool to identify entheseal affectation, capable of improving the diagnostic accuracy in SpA. Objectives To evaluate the construct validity of the enthesis ultrasound in the assessment of disease activity in SpA. Methods A longitudinal Achilles enthesis ultrasound study in patients with early SpA was undertaken. Achilles ultrasound examinations were performed at baseline, six- and twelve-month time periods and compared with clinical outcomes measures collected at basal visit. Results Bilateral Achilles enthesis of 146 early SpA patients (68 women) were analysed. Basal mean ± SD (range) BASFI, BASRI-spine, BASDAI, and ASDAS were 2.44±2.05 (0-8), 0.67±0.74 (0-3), 4.60±2.07 (0-9.5), 2.51±1.16 (0-5), respectively. Baseline mean visual analogic scale for pain and patient global disease assessment were 5.15±2.5 (range of 0-10) and 2.98±1.56 (range of 0-7), respectively. Mean erythrocyte sedimentation rate was 15.0±16.99 (0-109) mm/h and C-reactive protein was 8.67±16.98 (1-90) mg/l. At baseline Achilles Doppler signal and ultrasound structure alteration were statistically significantly associated with higher CRP and ESR levels. Patients with basal very high disease activity assessed by ASDAS (>3.5) had significantly higher Achilles total ultrasound score verified at baseline (p=0.04); and ASDAS