Table 2.
Baseline demographic, clinical and imaging variables in the FORCAST study population according to the presence or absence of radiographic progression in the spine
| ΔmSASSS progression rate=0 over ≥2 years N=204 |
ΔmSASSS progression rate >0 N=227 |
p Value | |
|---|---|---|---|
| Age (mean (SD)) | 39.8 (13.0) | 44.7 (11.5) | <0.0001 |
| Males (N (%)) | 142 (69.6%) | 176 (77.5%) | 0.06 |
| Symptom duration (mean (SD) years) | 16.2 (11.3) | 20.2 (11.4) | <0.001 |
| Duration of follow-up (mean (SD) (range) years) | 2.4 (1.0) (1.5–8.2) | 2.9 (1.3) (1.5–8.8) | <0.001 |
| Smokers* | |||
| Current, N (%) | 37 (22.3%) | 37 (20.1%) | 0.69 |
| Pack years smoked (mean (SD)) | 6.3 (9.4) | 6.7 (9.5) | 0.94 |
| N (%) smoked >10 pack years† | 38 (23.8%) | 47 (27.5%) | 0.45 |
| BASDAI (mean (SD)) | 5.1 (2.5) | 5.2 (2.4) | 0.89 |
| ASDAS (mean (SD)) | 3.7 (1.5) | 3.9 (1.4) | 0.12 |
| CRP (mean (SD) mg/L) | 13.2 (19.7) | 15.6 (20.4) | 0.08 |
| N (%) HLA-B27 positive‡ | 151 (84.8%) | 174 (83.3%) | 0.78 |
| N (%) on NSAIDs | 162 (79.4%) | 185 (81.5%) | 0.63 |
| N (%) on TNF-α inhibitor | 127 (62.3%) | 139 (61.2%) | 0.84 |
| mSASSS (mean (SD)) | 14.5 (22.7) | 19.5 (18.3) | <0.0001 |
| SPARCC SIJ inflammation (mean (SD))§ | 8.1 (9.8) | 6.9 (10.0) | 0.28 |
| N (%) with SPARCC SIJ≥2§ | 48 (45.7%) | 55 (44.4%) | 0.79 |
| SSS fat metaplasia (mean (SD))¶ | 2.5 (4.2) | 5.2 (7.0) | 0.003 |
| N (%) with SSS fat metaplasia ≥2¶ | 29 (27.6%) | 49(38.6%) | 0.09 |
| SSS erosion (mean (SD))¶ | 3.8 (4.2) | 2.4 (3.7) | 0.007 |
| N (%) with SSS erosion ≥2¶ | 40 (38.1%) | 33 (26.6%) | 0.06 |
| SSS backfill (mean (SD))¶ | 2.2 (3.3) | 3.5 (4.3) | 0.02 |
| N (%) with SSS backfill ≥2¶ | 22 (21%) | 36 (28.3%) | 0.22 |
| SSS ankylosis (mean (SD))¶ | 4.1 (7.2) | 6.3 (7.9) | 0.003 |
| N (%) with SSS ankylosis ≥2¶ | 27 (25.7%) | 55 (43.3%) | 0.006 |
*Data from 350 patients.
†Data from 331 patients.
‡Data from 387 patients.
§Data from 229 patients.
¶Data on 232 patients.
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; mSASSS, modified Stoke Ankylosing Spondylitis Spine Score; NSAID, non-steroidal anti-inflammatory drug; SIJ, sacroiliac joints; SPARCC, Spondyloarthritis Research Consortium of Canada; SSS, SPARCC MRI SIJ Structural Scoring; TNF, tumour necrosis factor.