Demographics of study population
| All | Non-progressors, 2-year mSASSS change=0 | Progressors, 2-year mSASSS change>0 | P values | |
| N | 122 | 43 | 79 | |
| Mean (SD) or n (%) | ||||
| Male | 86 (70%) | 30 (70%) | 56 (71%) | 0.90 |
| Age (years) | 45 (12) | 42 (12) | 47 (12) | 0.04 |
| HLA-B27 positive | 97 (82%) | 36 (84%) | 61 (80%) | 0.64 |
| Symptom duration (years) | 23 (12) | 21 (14) | 25 (11) | 0.23 |
| Disease duration (years) | 14 (9) | 13 (11) | 15 (8) | 0.24 |
| NSAIDs | 95 (78%) | 35 (81%) | 60 (76%) | 0.49 |
| TNF-a treated | 11 (9%) | 3 (7%) | 8 (10%) | 0.56 |
| ASDAS-CRP | 2.6 (1.0) | 2.3 (1.0) | 2.7 (1.0) | 0.02 |
| BASDAI (0–10) | 3.4 (2.0) | 3.0 (2.0) | 3.6 (2.0) | 0.11 |
| Patient’s global assessment of disease activity (0–10) | 3.7 (2.6) | 3.4 (2.7) | 4.0 (2.6) | 0.19 |
| Spinal pain (0–10) | 3.5 (2.3) | 3.1 (2.5) | 3.7 (2.2) | 0.17 |
| ESR (mm/h) | 14.4 (14.6) | 12.0 (12.0) | 15.7 (15.8) | 0.07 |
| CRP (mg/L) | 13.7 (20.2) | 8.1 (9.2) | 16.7 (23.6) | 0.03 |
| C1M (nmol/L) | 59.2 (38.2) | 48.0 (21.9) | 65.4 (43.5) | 0.04 |
| C5M (nmol/L) | 5.6 (3.9) | 5.3 (1.8) | 5.7 (4.7) | 0.76 |
| C6M (nmol/L) | 10.6 (19.7) | 11.5 (29.2) | 10.1 (7.5) | 0.54 |
| VICM (nmol/L) | 11.7 (16.6) | 9.6 (7.8) | 12.8 (19.8) | 0.86 |
| mSASSS (0–72) | 13.9 (17.6) | 11.6 (20.1) | 15.1 (16.2) | 0.002 |
| mSASSS>0 | 106 (87%) | 32 (74%) | 74 (94%) | 0.003 |
Baseline refers to the baseline measurement of this study, when the biomarkers were assessed, which does not necessarily correspond to the baseline of the Outcome in Ankylosing Spondylitis International Study cohort.
ASDAS-CRP, ankylosing spondylitis disease activity score-C-reactive protein; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; CRP, C-reactive protein; C1M, C5M and C6M, MMP-mediated degradation of type I, V and VI collagen, respectively; ESR, erythrocyte sedimentation rate; HLA, human leucocyte antigen; mSASSS, modified Stoke Ankylosing Spondylitis Spine Score; MMP, matrix metalloproteinase; NSAIDs, non-steroidal anti-inflammatory drugs; TNF-a antitumour necrosis factor; VICM, citrullinated and MMP-degraded vimentin.