Disease characteristics of the patients included in the analyses
| Total number of patients (n=582) | |
|---|---|
| Age (years) at inclusion, mean±SD | 31.5 (7.2) |
| Male, n (%) | 297 (51.0) |
| Symptom duration (months) at first visit, mean±SD | 18.2 (10.6) |
| HLA-B27 positive, n (%) | 338 (58.1) |
| Positive family history SpA, n (%) | 146 (25.1) |
| IBP, n (%) | 582 (100) |
| Psoriasis, n (%) | 90 (15.5) |
| Dactylitis, n (%) | 74 (12.7) |
| Enthesitis, n (%) | 282 (48.5) |
| Uveitis, n (%) | 40 (6.9) |
| IBD, n (%) | 29 (5.0) |
| Elevated CRP, n (%) | 168 (30.6) |
| Good response to NSAIDs, n (%) | 459 (78.9) |
| Peripheral arthritis, n (%) | 100 (17.2) |
| Sacroiliitis present on radiograph, n (%) | 126 (21.6) |
| Positive MRI (ASAS definition), n (%) | 210 (36.1) |
ASAS, Assessment of SpondyloArthritis; CRP, C-reactive protein; IBP, inflammatory back pain; NSAIDs, non-steroidal anti-inflammatory drugs.