Table 7.

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.