Table 2.

Cox regression analysis for TNFi discontinuation in the whole group of patients with SpA, stratified by reason for discontinuation. Values are HR (95% CI).

Variables	All Reasons		Inefficacy		Adverse Events
Variables	Univariate	Final Model after Backward Selection	Univariate	Final Model after Backward Selection	Univariate	Final Model after Backward Selection
Sex, male vs female	0.63 (0.52–0.77)^{^c}	0.68 (0.55–0.84)^{^c}	0.45 (0.34–0.61)^{^c}	0.60 (0.44–0.82)^{^b}	0.79 (0.57–1.11)^**	0.57 (0.40–0.81)^{^b}
Age, per 10 yrs	1.01 (0.93–1.09)		1.04 (0.92–1.17)		1.00 (0.73–1.38)
Symptom duration, < vs ≥ 5 yrs	1.20 (0.97–1.48)^*		1.41 (1.03–1.92)^{^a}		0.95 (0.67–1.35)
TNFi agent
ETN vs other	1.65 (1.30–2.10)^{^c}	1.56 (1.22–1.99)^{^c}
IFX, ref			1.00 (ref)	1.00 (ref)	1.00 (ref)	1.00 (ref)
ETN			3.16 (2.21–4.51)^{^c}	2.67 (1.86–3.84)^{^c}	0.52 (0.31–0.90)^{^a}	0.52 (0.30–0.89)^{^a}
ADA			1.89 (1.23–2.90)^{^b}	1.74 (1.13–2.68)^{^a}	0.38 (0.20–0.73)^{^b}	0.34 (0.18–0.64)^{^b}
GOL			4.38 (2.17–8.81)^{^c}	3.53 (1.74–7.18)^{^c}	0.25 (0.04–1.78)^**	0.24 (0.04–1.69)^**
Clinical diagnosis
AS vs other	0.77 (0.63–0.94)^{^a}
AS, ref			1.00 (ref)		1.00 (ref)
PsA			1.55 (1.10–2.16)^{^a}		0.93 (0.66–1.32)
Other			2.31 (1.53–3.48)^{^c}		0.85 (0.50–1.45)
Year of TNFi therapy start, per 2 yrs	1.12 (1.04–1.20)^{^b}		1.30 (1.17–1.44)^{^c}		0.89 (0.79–1.01)^*
Previous csDMARD, yes vs no	0.96 (0.78–1.17)		1.88 (1.33–2.66)^{^c}		0.61 (0.44–0.85)^{^b}	0.68 (0.47–0.99)^{^a}
MTX co-therapy, yes vs no	0.84 (0.68–1.04)^*	0.69 (0.55–0.87)^{^b}	1.18 (0.86–1.62)		0.55 (0.38–0.79)^{^b}	0.60 (0.39–0.91)^{^a}
Axial disease, yes vs no	0.86 (0.65–1.16)		0.65 (0.44–0.97)^{^a}		1.15 (0.65–2.04)
Peripheral disease, yes vs no	1.44 (1.13–1.83)^{^b}	1.47 (1.14–1.91)^{^b}	2.25 (1.49–3.38)^{^c}	1.91 (1.25–2.90)^{^b}	0.90 (0.63–1.29)
CRP, > vs ≥ 1.2 mg/dl	0.78 (0.62–0.99)^{^a}	0.81 (0.64–1.03)^*	0.80 (0.57–1.13)		0.81 (0.56–1.18)
VAS global, > vs ≤ 60	1.16 (0.92–1.46)		1.64 (1.15–2.34)^{^b}	1.47 (1.03–2.10)^{^a}	0.91 (0.64–1.30)
PGA, > vs ≤ 2	1.03 (0.81–1.30)		1.13 (0.72–1.77)		0.87 (0.61–1.26)

↵* p < 0.1.
↵** p < 0.2.
↵a p < 0.05.
↵b p < 0.01.
↵c p < 0.001. TNFi: tumor necrosis factor inhibitor; SpA: spondyloarthritis; IFX: infliximab; ETN: etanercept; ADA: adalimumab; GOL: golimumab; AS: ankylosing spondylitis; PsA: psoriatic arthritis; csDMARD: conventional synthetic disease-modifying antirheumatic drugs; MTX: methotrexate; CRP: C-reactive protein; VAS: visual analog scale; PGA: physician’s global assessment.