THE DIAGNOSTIC VALUE OF CLINICAL EXAMINATION AND ULTRASOUND STUDY OF ENTHESES FOR EARLY DETECTION OF PSORIATIC AND RHEUMATOID ARTHRITIS: REMARC STUDY
The diagnosis of enthesitis can help in differentiating early psoriatic arthritis (ePsA) from early rheumatoid arthritis (eRA). Objective. To estimate the diagnostic value of detecting enthesitis during clinical examination and ultrasound in ePsA and eRA. Subjects and methods. The trial included 36 patients with ePsA and 33 with eRA. Entheses were evaluated using the Leeds Enthesitis Index (LEI): lateral humeral epicondyle and medial femoral condyle (MFC), Achilles tendon insertion site (ATAP), and plantar fascia (PF) point on the right and on the left. Enthesitis (on ultrasound) presented with thickening, reduced echo density, and vascularization at Doppler energy imaging. DAS, DAS28, SDAI, CDAI, M+SD, Me [25th, 75th percentile], t-test, Fisher''s exact test, χ <sup>2</sup> test, U test, and Spearman correlation coefficients (R) were calculated; the value p < 0.05 was considered statistically significant. Results. Clinical examination revealed enthesitis in 41.6% of the patients with ePsA and in 39.4% of those with eRA (p > 0.05). No significant differences were found between ePsA and eRA according to LEI (0.5 [0; 2] and 1 [0; 2] and to LEI+PF (1 [0; 2] and 1 [0; 2], respectively). Enthesitis of MFC and PF was significantly more frequently detected in ePsA than in eRA — 12 (33.3%)/2 (6.1%) and 10 (27.8%)/2 (6.1%) patients, respectively. In eRA versus ePsA, enthesitis of MFC was more frequently found (16 (48.4%) and 8 (22.2%) patients), respectively. Ultrasound revealed no significant differences between the groups in enthesitis. In ePsA, there was a significant correlation between DAS, DAS28, SDAI, CDAI, LEI, and LEI+PF. Conclusion. Enthesis ultrasound cannot differentiate ePsA from eRA. Clinical examination more frequently detects enthesitis in the knee joints in eRA and in the calcaneal region in ePsA.