Effect of Enthesitis on 1505 Brazilian Patients with Spondyloarthritis

Objective. To analyze the clinical effect of enthesitis in a large Brazilian cohort of patients with spondyloarthritis (SpA). Methods. A common protocol of investigation was prospectively applied to 1505 patients with SpA in 29 centers in Brazil. Clinical and demographic variables and disease indexes were investigated. The Maastricht Ankylosing Spondylitis Enthesitis Score was used to investigate the enthesitis component. Ankylosing spondylitis was the most frequent disease in the group (65.4%). Others were psoriatic arthritis (18.4%), undifferentiated SpA (6.7%), reactive arthritis (3.3%), and enteropathic arthritis (3.2%). Results. At least 1 affected enthesis was observed in 54% of the patients with SpA, with a mean of 2.12 +/- 2.98 entheses affected. According to the clinical presentation, enthesitis was significantly more frequent in patients with axial + peripheral joint involvement compared to isolated axial or peripheral involvement (p < 0.001). There was a statistical association between the presence of enthesites and axial symptoms (buttock pain, cervical pain, and hip pain), and peripheral symptoms (lower limb arthritis, number of painful and swollen joints; p < 0.05). Patients with enthesitis also presented higher mean scores of Bath Ankylosing Spondylitis Functional Index (BASFI; p < 0.001), Bath Ankylosing Spondylitis Disease Activity Index (p < 0.001), and Ankylosing Spondylitis Quality of Life (ASQoL; p < 0.001). Multivariate logistic regression showed that BASFI (p < 0.0001; OR 74.839), ASQoL (p = 0.0001; OR 14.645), and Achilles tendonitis (p = 0.0059; OR 7.593) were associated with work incapacity. Conclusion. The clinical presence of enthesitis in this large cohort of patients with SpA was frequent and was associated with a significant increase in disease activity and decline in functional capacity and quality of life.