AB0751 ASSOCIATION OF AXIAL INVOLVEMENT WITH MORE SEVERE DISEASE: HIGH DISEASE ACTIVITY, SEVERE PERIPHERAL ARTHRITIS AND WORSE SKIN LESION. DATA FROM THE RUSSIAN PSORIATIC ARTHRITIS REGISTRY (RU-PSART)

Background The latest data show that axial involvement in psoriatic arthritis (PsA) patients (pts) is associated with significantly more severe disease status (1). Objectives To analyze, in clinical practice, disease activity and characteristics of PsA pts with and without radiographic sacroiliitis (rSI). Methods 385 pts (M/F–172/213) with PsA according to CASPAR criteria were included in the RU-PsART. Data was collected from 25 rheumatology clinics from various regions of the Russian Federation. Median age 45 (Min 20-Max 80) years (yrs), disease duration 3.4 yrs (4 months-32 yrs). Pts underwent standard clinical examination of PsA activity. Disease activity was measured by DAPSA, DAS28, BASDAI. The examination involved HLA B27 antigen status and X-ray of sacroiliac joints (pelvic radiographs). rSI was defined as bilateral grade ≥2 or unilateral grade ≥3. Skin lesion severity was evaluated in terms of body surface area (BSA) affected, and Psoriasis area Severity index (PASI). When BSA was ≥3%, PASI was calculated. Pts were split into two groups (gr.): those with rSI [rSI(+)] and those without rSI [rSI(-)]. Gr. rSI(+) included 214 (55.6%) cases (M/F–106/108), gr. rSI(-) 171 (44.4%) cases (M/F– 66/105). Median age in gr. rSI(+) was 45 [Min 20-Max 80] yrs, in gr. rSI(-) it was 46 [Min 20-Max 82] yrs. Medians and quartiles [Me (Q25; Q75)], [Min; Max], U-test and ORs with 95% CI were performed. All CI >1, p Results Significant differences were revealed between gr. rSI(+) and gr. rSI(-). In HLA-В27 antigen status: in gr. rSI(+) it was positive in 62 pts, negative in 64 pts, while in gr. rSI(-) it was positive in 26 pts, negative in 52 pts. OR 1.9 [1.1-3.5]. In tender joint count (TJC): in gr. rSI(+) TJC was 9 [14-18], in gr. rSI(-) it was 6 [3-12] (р=0.02). in disease activity measured by DAPSA: in gr. rSI(+) DAPSA was 28.40 [15.65-43.65], in gr. rSI(-) it was 20.0 [12.45-30.0] (р=0.00). In DAS28: in gr. rSI(+) DAS28 was 4.3 [3.3-5.6], in gr. rSI(-) it was 4.1 [3.0-4.9] (р=0.02).]. In disease activity measured by BASDAI: in gr. rSI(+) BASDAI was 1.6 [0-5.1], in gr. rSI(-) it was 0 [0-4.5] (р=0.00). In frequency of erosive radiographic arthritis of feet: in gr. rSI(+) 58 pts had erosive arthritis of feet, 156 did not have, while in gr. rSI(-) 29 pts had erosive arthritis of feet, and 142 did not have. OR 1.8 [1.1-3.0]. In more extensive skin lesion area: in gr. rSI(+) BSA 3% had 94 pts; while in gr. rSI(-) BSA 3% had 57 pts. OR 0.6 [0.4-0.97]. In CRP: in gr. rSI(+) CRP was 0.9 [0.4-2.2] mg/dl, in gr. rSI(-) it was 0.8 [0.3-1.3] mg/dl (p=0.03). Conclusion Axial involvement in PsA patients is associated with HLA-B27 positivity. Patients with axial involvement have significantly worse disease status as measured by disease activity and a higher CRP level; they are more likely to have more severe (erosive) peripheral arthritis and more extensive skin lesion area. Early detection of axial involvement is critical for choice of treatment approach and good prognosis. Reference [1] P. J. Mease, et al. J Rheumatol2018;45:1389-96 Disclosure of interests ELENA GUBAR: None declared, Elena Loginova Speakers bureau: Novartis, Celgene Corporation, Biocad, Janssen, abbVie inc, anastasia Koltakova: None declared, Yulia Korsakova Speakers bureau: Celgene Corporation, Janssen, Tatiana Korotaeva Consultant for: Pfizer, MSD, Novartis, abbVie, Celgene, Biocad, Janssen, UCB, Lilly and Novartis-Sandoz, Speakers bureau: Pfizer, MSD, Novartis, abbVie, Celgene, Biocad, Janssen, UCB, Lilly and Novartis-Sandoz, Evgeny Nasonov Speakers bureau: Pfizer, inc., MSD, Novartis, abbVie inc., Celgen Corporation, Biocad, Janssen, UCB, inc., Maria Sedunova: None declared, Igor Pristavsky: None declared, Irina Umnova: None declared, Irina Bondareva: None declared, Snezana Kudishina: None declared