POS1073 AXIAL PSORIATIC ARTHRITIS AND ANKYLOSING SPONDYLITIS. SAME OR DIFFERENT? A REAL-WORLD STUDY WITH EMPHASIS ON COMORBIDITIES
Authors: G. E. Fragoulis, M. Pappa, G. Evangelatos, A. Iliopoulos, P. Sfikakis, M. Tektonidou
Journal: Annals of the Rheumatic Diseases (2021)

Background: Axial involvement affects 25-70% of psoriatic arthritis (PsA) patients, depending on the criteria used for its definition. Efforts are underway to clarify the similarities and differences between axial-PsA and ankylosing spondylitis (AS). Objectives: We aimed to compare, in a real-world setting, axial-PsA and AS, in terms of demographic, radiologic and clinical (musculoskeletal and extra-articular) characteristics, with a focus on comorbidities. Methods: All AS (New York criteria, n=128) and PsA patients (CASPAR criteria, n=78) with axial involvement who were regularly followed-up in the outpatients’ rheumatology clinics from two tertiary hospitals (December 2018-July 2020) were included. Axial-PsA was defined when both of the following were ever present: inflammatory axial symptoms and radiological findings in X-ray or MRI of the sacroiliac joints or the spine. The following findings were considered: sacroiliitis (unilateral ≥ grade 3 or bilateral ≥ grade 2), corner lesions or squaring in the vertebrae, syndesmophytes (marginal or para-marginal) and facet joints arthritis. Demographic, radiologic and clinical characteristics including comorbidities were compared between AS and axial-PsA. For comorbidities (Major Adverse Cardiovascular Events [MACE: combined coronary disease and cerebrovascular accidents], hypertension, diabetes mellitus, dyslipidemia, depression, osteoporosis, and malignancies), adjustments were made for relevant confounders as follows: MACE were adjusted for: age, gender, smoking, hypertension, dyslipidemia, disease duration, DM and non-steroidal anti-inflammatory drugs [NSAIDs] use; depression for: age, gender and disease duration; malignancy for: age, gender, disease duration; hypertension for: age, sex, BMI, NSAIDs use, smoking for; DM: age, sex, BMI, glucocorticoids treatment; osteoporosis for: age, sex, glucocorticoids treatment. Statistical significance is considered for p-values less than 0.05 and 0.1 in univariate and multivariate analyses, respectively. Results: AS patients were younger (p=0.05) and were diagnosed at a younger age (p=0.002), more frequently of male gender (p=0.04), had lower BMI (p=0.006) and they were more frequently HLA-B27-positive (p=0.006). In AS patients, peripheral arthritis, dactylitis and nail involvement were less common (p=0.001 for all), in contrast to eye (p=0.001) and bowel involvement (p=0.004). Frequency of radiologic abnormalities in the spine was similar between the two groups while sacroiliitis was more often bilateral in AS and unilateral in axial-PsA (p&lt;0.001 for both) Comorbidities, including MACE, were comparable between AS and axial-PsA, apart from depression which was more frequent in axial-PsA (Table 1. next page). Table 1. Comorbidities. Comparison between axial-PsA and AS. OR: odds ratio, MACE: Major cardiovascular events. * adjustments are reported in the text Comorbidities axial-PsA (n=79 ) AS (n=129 ) Crude OR (95%CI ) Adjusted OR (95%CI ) p-value MACE* n (%) 4 (5.1) 6 (4.6) 0.91 (0.25-3.34) 1.73 (0.32-9.34) 0.526 Dyslipidemia n (%) 37 (46.8) 45 (34.9) 0.61 (0.34-1.07) NA 0.108 Hypertension* n (%) 27 (34.2) 24 (18.6) 0.44 (0.23-0.83) 1.11 (0.38-3.21) 0.843 Diabetes mellitus* n (%) 12 (15.2) 10 (7.7) 0.47 (0.19-1.14) 1.65 (0.43-6.29) 0.463 Depression* n (%) 19 (24.1) 16 (12.4) 0.44 (0.21-0.93) 0.48 (0.22-1.07) 0.07 Osteoporosis* n (%) 3 (3.8) 10 (7.7) 2.13 (0.57-7.98) 2.40 (0.56-10.18) 0.235 Malignancies* n (%) 3 (3.8) 3 (2.3) 0.60 (0.12-3.06) 0.87 (0.16-4.70) 0.870 Conclusion: AS and axial-PsA have certain clinical and radiologic differences. Comorbidities were comparable, while depression was more common in axial-PsA. Disclosure of Interests: George E. Fragoulis: None declared, Maria Pappa: None declared, Gerasimos Evangelatos: None declared, Alexios Iliopoulos: None declared, Petros Sfikakis Grant/research support from: AbbVie, Pfizer, MSD, Roche, UCB, GSK, Novartis, Maria Tektonidou Grant/research support from: AbbVie, GSK, Genesis, MSD, Novartis, Pfizer, UCB.