Table 5.

Interactions with baseline characteristics and spinal radiographic progression with generalized estimating equations model among male patients with ankylosing spondylitis (n=85)

Variable	Univariate analysis			Multivariable analysis
	β (95% CI)	p-value		β (95% CI)	p-value
Time	1.78 (1.10∼2.46)	<0.001		−1.57 (−5.03∼1.90)	0.375
Time*current smoker	−0.414 (−1.73∼0.90)	0.539
Time*uveitis	0.04 (−1.32∼1.40)	0.954
Time*enthesitis	−1.02 (−1.87∼−0.17)	0.018		0.19 (−0.57∼0.95)	0.619
Time*peripheral arthritis	−1.31 (−2.46∼−0.17)	0.025		−0.34 (−1.23∼0.56)	0.459
Time*hip arthritis	−0.38 (−1.83∼1.08)	0.612
Time*leptin/100	0.00 (0.00∼0.01)	0.383
Time*Dkk1/100	−0.13 (−0.20∼−0.05)	0.001		−0.10 (−0.15∼−0.04)	0.001
Time*estrogen	−0.01 (−0.03∼0.01)	0.272
Time*age at symptom onset	0.08 (0.02∼0.13)	0.004		0.03 (−0.01∼0.08)	0.109
Time*initial ESR	0.01 (−0.01∼0.03)	0.468
Time*initial CRP	0.22 (0.07∼0.38)	0.005		0.11 (0.00∼0.23)	0.050
Time*BMI	0.19 (0.03∼0.36)	0.021		0.13 (0.01∼0.26)	0.039
Time*initial mSASSS	0.03 (−0.02∼0.08)	0.189		0.21 (0.02∼0.40)	0.030

Dkk1: dickkopf-1, ESR: erythrocyte sedimentation rate, CRP: C-reactive protein, BMI: body mass index, mSASSS: modified Stoke Ankylosing Spondylitis Spine Score, CI: confidence interval.