Extra-articular disease in patients with spondyloarthritis. Baseline characteristics of the spondyloarthritis cohort of the AQUILES study.

OBJECTIVES To describe the prevalence of extra-articular disease (uveitis, psoriasis and inflammatory bowel disease [IBD]), in a cohort of patients with spondyloarthritis (SpA). PATIENTS AND METHODS AQUILES is an observational, prospective and multicentric study of three cohorts of patients with one of the following immune-mediated inflammatory diseases (IMID): SpA, psoriasis, or IBD. In the present cohort, patients ≥18 years of age with SpA were enrolled from Rheumatology clinics. The main objective was to assess the coexistence of these diseases and of uveitis, based on the patients' clinical history up to the study entry. RESULTS A total of 601 patients with SpA (men: 63.1%; women: 36.9%) were enrolled. The specific diagnoses were: ankylosing spondylitis (55.1%), psoriatic arthritis (25.1%), undifferentiated spondyloarthritis (16.1%), enteropathic arthritis (2.5%), and others (1.3%). In 43.6% (95% CI: 39.7-47.6) of the patients, at least one of the three abovementioned diseases was encountered, predominantly psoriasis (prevalence 27.8%, 95% CI: 24.4-31.5), uveitis (13.6%, CI 95%: 11.1-16.6) and IBD (5.1%, 95% CI: 3.7-7.2). In patients with ankylosing spondylitis the proportion of other disease was 25.3% (IBD: 3.9%, psoriasis: 5.4%, uveitis: 19.0%) whilst it was 94.7% in psoriatic arthritis, due to the presence of psoriasis (94.0%). The coexistence of these diseases was associated with age, female gender and the presence of other extra-articular manifestations associated with SpA. CONCLUSIONS Extra-articular disease in patients with SpA is common and, in this study, it was associated to age, female gender and the presence of other SpA-related extra-articular manifestations.