Clinical, laboratory and imaging parameters at baseline in FORCAST patients matched for age, symptom duration and follow-up duration according to the presence (damage) or absence (lack of damage) of any syndesmophytes or ankylosis on cervical and lumbar spine radiographs*
| Damage (n=81) | Lack of damage (n=42) | p Value | |
|---|---|---|---|
| Age (mean (SD)) | 41.80 (8.64) | 39.48 (9.03) | 0.13 |
| Males (N (%)) | 66 (82.5%) | 24 (57.0%) | 0.004 |
| Smoking pack years (mean (SD)) | 6.92 (9.49) | 5.69 (9.12) | 0.94 |
| Current smoker (N (%)) | 15 (23.4%) | 8 (25.0%) | 1.000 |
| Pack years >10 (N (%)) | 21 (33.9%) | 5 (16.1%) | 0.089 |
| TNFi treated (N (%)) | 50 (62.5%) | 23 (54.8%) | 0.44 |
| NSAID treated (N (%)) | 65 (81.2%) | 33 (78.6%) | 0.81 |
| HLA-B27 positive (N (%)) | 58 (81.7%) | 29 (76.3%) | 0.617 |
| BASDAI (mean (SD)) | 5.38 (2.49) | 5.09 (2.52) | 0.44 |
| ASDAS (mean (SD)) | 4.00 (1.34) | 3.44 (1.56) | 0.061 |
| CRP (mean (SD)) | 14.32 (15.89) | 9.22 (10.74) | 0.02 |
| SPARCC SIJ inflammation (mean (SD)) | 6.04 (9.03) | 7.54 (8.46) | 0.22 |
| SPARCC SIJ>2 (N (%)) | 16 (35.6%) | 15 (55.6%) | 0.14 |
| SSS fat metaplasia (mean (SD)) | 4.69 (6.23) | 1.91 (3.44) | 0.029 |
| SSS fat metaplasia ≥2 (N (%)) | 18 (40.0%) | 6 (20.7%) | 0.13 |
| SSS erosion (mean (SD)) | 2.69 (3.98) | 4.16 (3.74) | 0.019 |
| SSS erosion ≥2 (N (%)) | 14 (31.1%) | 14 (48.3%) | 0.15 |
| SSS backfill (mean (SD)) | 4.22 (4.92) | 1.76 (2.25) | 0.051 |
| SSS backfill ≥2 (N (%)) | 13 (28.9%) | 5 (17.2%) | 0.28 |
| SSS ankylosis (mean (SD)) | 8.98 (8.92) | 2.41 (4.60) | 0.003 |
| SSS ankylosis >2 (N (%)) | 24 (53.3%) | 6 (20.7%) | 0.007 |
*Mean (SD) duration of symptoms and prospective follow-up was 18.0 (7.0) and 2.3 (0.49) years in those cases lacking damage and 17.5 (8.2) and 2.6 (1.4) years in those with damage.
ASDAS, Ankylosing Spondylitis Disease Activity Score; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; CRP, C-reactive protein; FORCAST, Follow Up Research Cohort in Ankylosing Spondylitis; HLA, human-leucocyte-antigen; NSAID, non-steroidal anti-inflammatory drug; SPARCC, Spondyloarthritis Research Consortium of Canada; SSS, SPARCC MRI SIJ Structural Scoring; TNFi, tumour necrosis factor inhibitor.