Table 2.

Variables associated with treatment failure

	Univariable analysis			Multivariable analysis
Variables	p	HR	95% CI	p	HR	95% CI
Male	0.013	3	1.3–7	0.001	5.3	2.1–13.7
IBD type [UC vs CD]	0.010	2.7	1.3–5.8	0.001	3.9	1.7–8.9
CD locationa	0.281
CD behaviora	0.657
Age at diagnosis	0.461
Age at start of IFX	0.439
Disease duration	0.433
UC extensiona	0.264
Perianal fistulizing disease	0.293
Prior ileocolonic resection	0.549
Concomitant IMMsb	0.094
Anti-TNF naïve	0.685
Smoking ever	0.524
IFX dosing other than 5 mg/kg q8wb	0.422
IFX concentrationb	0.039	0.93	0.87–0.99	0.006	0.89	0.82–0.97
ATIb	0.845
Proactive IFX monitoring following reactive testing	0.001	0.17	0.05–0.55	0.002	0.15	0.05–0.51
Center	0.503
Type of assayb	0.243

^aMontreal Classification; ^bat start of therapeutic drug monitoring.

IBD: inflammatory bowel disease; CD: Crohn’s disease; UC: ulcerative colitis; HR: hazard ratio; CI: confidence interval; IFX: infliximab; IMM: immunomodulator; TNF: tumor necrosis factor; ATI: antibodies to infliximab; w: week.