Table 3.

Correlation between change from baseline in SPARCC SIJ score or CRP and change in clinical and SPARCC SSS measures, ETN/ETN group

		Δ SPARCC SIJ		Δ CRP
		N	R	N	R
ASDAS	Week 12 Δ	94	0.35†	98	0.61†
	Week 48 Δ	88	0.58†	89	0.58†
BASDAI	Week 12 Δ	97	0.27*	100	0.22‡
	Week 48 Δ	90	0.42†	90	0.30*
BASMI	Week 12 Δ	94	0.07	97	0.34†
	Week 48 Δ	88	0.14	88	0.28*
BASFI	Week 12 Δ	97	0.17	100	0.20‡
	Week 48 Δ	90	0.35†	90	0.20
Total back pain	Week 12 Δ	97	0.28*	100	0.20‡
	Week 48 Δ	90	0.45†	90	0.20
CRP	Week 12 Δ	96	0.31*
	Week 48 Δ	89	0.37†
ASAS40	Week 12 Δ	97	−0.30*	100	−0.19
	Week 48 Δ	90	−0.39†	90	−0.16
SSS Fat metaplasia	Week 48 Δ	88	−0.28*	87	−0.07
SSS Erosion	Week 48 Δ	88	0.57†	87	0.25‡
SSS Ankylosis	Week 48 Δ	88	0.11	87	−0.08
SSS Backfill	Week 48 Δ	88	−0.61†	87	−0.20

*p<0.01, †p<0.001, ‡p<0.05.

Clinical measures used observed case population. SSS scores include baseline and week 48; no values from an early termination visit were included.

For change from baseline to week 12 in the PBO/ETN group, the significant correlations were R=0.37 for CRP/ASDAS and R=0.22 for SPARCC SIJ/CRP. For change from baseline to week 48 in the PBO/ETN group, the significant correlations were: R=0.24 for SPARCC SIJ/ASDAS; R=0.32 for SPARCC SIJ/CRP; R=−0.46 for SPARCC SIJ/fat metaplasia; R=0.55 for SPARCC SIJ/erosion; R=−0.43 for SPARCC SIJ/backfill; R=0.62 for CRP/ASDAS; R=0.31 for CRP/BASDAI; and R=0.30 for CRP/BASFI.

ASAS40, Assessment of SpondyloArthritis international Society 40; ASDAS, Ankylosing Spondylitis Disease Activity Score; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASFI, Bath Ankylosing Spondylitis Functional Index; BASMI, Bath Ankylosing Spondylitis Metrology Index; CRP, C-reactive protein; ETN, etanercept; PBO, placebo; R, Spearman correlation; SIJ, sacroiliac joint; SPARCC, Spondylitis Research Consortium of Canada; SSS, SPARCC MRI SIJ structural score.