Patient characteristics and disease outcomes at month 72 if not stated otherwise
| Characteristic | N | n (%) or mean (SD) |
| Female gender | 384 | 207 (54%) |
| Age (years) | 384 | 40.3 (8.7) |
| Symptom duration (years) | 382 | 7.5 (0.9) |
| University education or equivalent (at baseline) | 382 | 242 (63%) |
| Currently employed | 381 | 324 (85%) |
| BMI (kg/m²) | 377 | 24.9 (4.6) |
| Current smoking | 372 | 107 (29%) |
| History of smoking | 372 | 185 (50%) |
| HLA-B27 positive | 383 | 244 (64%) |
| Current arthritis | 374 | 18 (5%) |
| History of arthritis | 382 | 164 (43%) |
| History of inflammatory bowel disease | 384 | 46 (12%) |
| History of psoriasis | 384 | 115 (30%) |
| History of uveitis | 384 | 74 (19%) |
| History of dactylitis | 384 | 87 (23%) |
| Enthesitis score* | 363 | 3.0 (5.2) |
| CRP (mg/L) | 325 | 4.9 (7.5) |
| ASDAS | 322 | 2.0 (1.0) |
| BASDAI (0–10) | 383 | 3.4 (2.1) |
| BASFI (0–10) | 382 | 2.3 (2.1) |
| BASMI (0–10) | 350 | 2.4 (1.0) |
| HAQ-AS (0–3) | 384 | 0.5 (0.5) |
| ASAS HI (0–17) | 384 | 5.8 (4.0) |
| Good overall functioning (ASAS HI≤5) | 384 | 191 (50%) |
| Moderate overall functioning (5<ASAS HI <12) | 384 | 155 (40%) |
| Bad overall functioning (ASAS HI≥12) | 384 | 38 (10%) |
| Sacroiliitis according to mNY criteria (at month 60) | 339 | 71 (21%) |
| Active sacroiliitis on MRI (ASAS criteria; at month 60) | 132 | 31 (23%) |
| mSASSS (0–72; at month 60) | 317 | 1.0 (3.7) |
| MRI spinal inflammation (Berlin score; at month 60) | 134 | 0.5 (1.0) |
| TNFi treatment within last 12 months | 383 | 188 (49%) |
| NSAID intake within last 12 months | 382 | 253 (66%) |
| csDMARD intake within last 12 months | 384 | 76 (20%) |
*Concise Mander Enthesitis Score with gradation.
ASAS HI, Assessment of SpondyloArthritis International Society Health Index; ASDAS, Ankylosing Spondylitis Disease Activity Score; BASDAI, Bath Ankylosing Spondylitis Disease Activity Score; BASFI, Bath Ankylosing Spondylitis Functional Index; BASMI, Bath Ankylosing Spondylitis Metrology Index; BMI, body mass index; CRP, C reactive protein; csDMARD, conventional synthetic disease-modifying anti-rheumatic drug; HAQ-AS, Ankylosing Spondylitis Health Assessment Questionnaire; HLA, human leucocyte antigen; mNY, modified New York; mSASSS, modified Stoke Ankylosing Spondylitis Spine Score; N, number; NSAID, non-steroidal anti-inflammatory drug; TNFi, tumour necrosis factor inhibitor.