Baseline patient characteristics in the SPACE and DESIR cohorts
| SPACE (n=465) | DESIR (n=576) | |
| Age at baseline (years) | 30 (8) | 33 (8) |
| Male gender | 126 (45) | 269 (47) |
| Symptom duration (years) | 1.8 (2.0) | 1.5 (0.8) |
| ASAS axSpA criteria | 172 (37) | 358 (62) |
| axSpA according to rheumatologist* | 136 (52) | 269 (47) |
| ASAS pSpA criteria | 182 (39) | 320 (56) |
| ASAS SpA criteria† | 249 (54) | 443 (77) |
| Sacroiliitis on MRI-SIJ (ASAS) | 64 (14) | 153 (27) |
| BME on MRI-Spine (≥5 lesions) | 21 (5) | 25 (4) |
| Radiographic sacroiliitis (mNY) | 38 (8) | 78 (14) |
| ≥1 syndesmophyte on X-Spine | 15 (3) | 39 (7) |
| Elevated CRP (≥6 mg/L) | 64 (24) | 169 (29) |
| Good response to NSAIDs ever | 189 (41) | 491 (85) |
| Peripheral arthritis ever | 41 (15) | 122 (21) |
| Dactylitis ever | 18 (6) | 78 (14) |
| Heel enthesitis ever | 55 (20) | 261 (45) |
| HLA-B27 | 156 (57) | 345 (60) |
| Family history of SpA | 123 (44) | 250 (43) |
| Psoriasis ever | 41 (15) | 99 (17) |
| Uveitis ever | 27 (10) | 52 (9) |
| Inflammatory bowel disease ever | 16 (6) | 25 (4) |
| Current arthritis/any enthesitis/dactylitis | 317 (68) | 398 (69) |
| Inflammatory back pain | 308 (66) | 576 (100) |
| Number of SpA features (0–9)‡ | 2 (1) | 3 (1) |
Values are mean (SD) for continuous variables or number (%) for binary variables. SpA features are positive if ‘ever present’ (any time in the past and/or baseline).
*Clinical diagnosis of axSpA at baseline with a level of confidence >7; missing data SPACE: symptom duration (n=461); missing data DESIR: axSpA according to rheumatologist (n=575).
†Fulfilment of either ASAS axSpA or ASAS pSpA classification criteria.
‡Peripheral arthritis, heel enthesitis, dactylitis, psoriasis, uveitis, inflammatory bowel disease, good response to NSAIDs, elevated CRP and family history of SpA.
ASAS, Assessment of SpondyloArthritis international Society; axSpA, axial spondyloarthritis; BME, bone marrow oedema; CRP, C reactive protein; mNY, modified New York criteria; NSAIDs, non-steroidal anti-inflammatory drugs; pSpA, peripheral spondyloarthritis; SIJ, sacroiliac joints; X-Spine, radiograph of the spine.