Table 2.

Significant differences between SpA subgroups

	AS (n=70)	PsA (n=39)	UDSpA (n=17)	p
uveitis (n)	10 (14.3%)	0 (0%)	1 (5.9%)	0.037
psoriasis (n)	3 (4.3%)	39 (100%)	1 (5.9%)	< 0.001
IBD (n)	1 (1.4%)	0 (0%)	2 (11.8%)	0.022
tendinitis (n)	0 (0%)	3 (7.7%)	2 (11.8%)	0.030
	aSpA (n=33)	pSpA (n=9)	mSpA (n=84)
psoriasis (n)	4 (12.1%)	4 (44.4%)	35 (41.7%)	0.008
tendinitis (n)	1 (3%)	2 (22.2%)	2 (2.4%)	0.014
	female (n=45)	male (n=81)
uveitis (n)	1 (2.2%)	10 (12.3%)		0.044
psoriasis (n)	21 (46.7%)	22 (27.2%)		0.027
	non-smoking (n=92)	smoking (n=34)
psoriasis (n)	27 (29.3%)	16 (47.1%)		0.043
	non-aSpA (n=9)	aSpA (n=117)
tendinitis (n)	2 (22.2%)	3 (2.6%)		0.041
	non-pSpA (n=33)	pSpA (n=93)
psoriasis (n)	4 (12.1%)	39 (41.9%)		0.002
	no X-ray SI (n=78)	X-ray SI (n=48)
psoriasis (n)	39 (50%)	4 (8.3%)		< 0.001
enthesitis (n)	1 (1.3%)	4 (8.3%)		0.049
	no arthritis (n=50)	arthritis (n=76)
psoriasis (n)	4 (8%)	39 (51.3%)		< 0.001
enthesitis (n)	4 (8%)	1 (1.3%)		0.040
tendinitis (n)	0 (0%)	5 (6.6%)		0.044
other (n)	0 (0%)	6 (7.9%)		0.042
Notes: scale variables are reported as “median (intequartile range)”, while nominal variables are reported as “frequency (subgroup percentage)”; p values represent the significance of Mann Whitney (scale variables) or χ2 (nominal variables).
Abbreviations: AS = ankylosing spondylitis, aSpA = axial spondyloarthritis, BASFI = Bath Ankylosing Spondylitis Functional Index, IBD = inflammatory bowel disease (Crohn disease, ulcerative colitis) mSpA = mixed (peripheral and axial) spondyloarthritis, PsA = psoriatic arthritis, pSpA = peripheral spondyloarthritis, SI = sacroiliitis, UDSpA = undifferentiated spondyloarthritis.