Impact of TNFi use within a 2-year radiographic interval on sacroiliac joint radiographic progression defined as a change of at least one grade in at least one SIJ and ignoring a change from 0 to 1
| Variable | OR | 95% CI | P value |
| TNFi use during X-ray interval ≥1 year (ref: no TNFi use during interval) | 0.21 | 0.08 to 0.55 | 0.001 |
| TNFi use during X-ray interval <1 year (ref: no TNFi use during interval) | 0.38 | 0.04 to 3.39 | 0.39 |
| Baseline sacroiliac damage at start of each X-ray interval (0–7) | 1.33 | 1.00 to 1.77 | 0.047 |
| Female sex | 0.27 | 0.07 to 1.00 | 0.05 |
| Symptom duration | 1.05 | 1.01 to 1.10 | 0.02 |
| Current smoking | 2.21 | 0.71 to 6.89 | 0.17 |
| HLA-B27 negative | 0.71 | 0.14 to 3.81 | 0.70 |
| NSAID use at start of each X-ray interval | 0.93 | 0.26 to 3.37 | 0.91 |
| ASDAS at start of each X-ray interval | 1.30 | 0.75 to 2.27 | 0.35 |
302 patients and 483 intervals (22 events).
ASDAS, Ankylosing Spondylitis Disease Activity Score; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; CRP, C-reactive protein; HLA-B27, human leucocyte antigen B27; NSAID, non-steroidal anti-inflammatory drug; SIJ, sacroiliac joint; TNFi, tumour necrosis factor inhibitor.