Significance of low level infliximab in the absence of anti-infliximab antibodies

Table 1 Background disposition and clinical characteristics n (%)

Parameter	Cases	Controls	P value	OR (95%CI)
Gender			0.19	2.0 (0.70-5.70)
Male	15 (50)	10 (33.3)
Female	15 (50)	20 (66.6)
Type of IBD			0.45	0.56 (0.12-2.57)
CD	25 (83.3)	27 (90.0)
UC	5 (16.7)	3 (10.0)
Duration of IFX therapy1 (mo)	21 ± 25.1	20.75 ± 25.5	0.97
Concomitant therapy	11 (36.7)	11 (36.7)	1.00	1.00 (0.35-2.86)
Episodic therapy	6 (20)	6 (20.0)	1.00	1.00 (0.28-3.54)
Median age (yr)	33 ± 15.2	28.5 ± 10.7	0.24
Median disease duration (yr)	10.5 ± 9	9 ± 7.7	0.65
Median age at diagnosis (yr)	22 ± 12.4	20 ± 9.7	0.19
CD - disease location
Ileal	9 (36)	8 (29.7)	0.62	1.30 (0.41-4.30)
Ileo-colonic	8 (32)	11 (40.7)	0.51	0.68 (0.22-2.10)
Colonic	8 (32)	8 (29.6)	0.85	1.10 (0.34-3.63)
CD - upper GI involvement	2 (8)	2 (7.4)	0.93	1.08 (0.14-8.40)
CD - anal/perianal involvement	13 (52)	14 (51.8)	0.99	1.00 (0.34-3.00)
CD - disease behavior
Non stricturing non penetrating	12 (48)	12 (44.5)	0.79	1.15 (0.38-3.43)
Stricturing	8 (32)	10 (37.0)	0.70	0.80 (0.25-2.50)
Penetrating	5 (20)	5 (18.5)	0.89	1.10 (0.28-4.40)
UC - disease location
Proctitis	0	0
Left-sided colitis	2 (40)	1 (33.3)
Extensive colitis	3 (60)	2 (66.7)
Extra-intestinal manifestations	15 (50)	15 (50.0)	1.00	1.00 (0.36-2.75)
Smoking	2 (6.7)	5 (16.7)	0.24	0.30 (0.06-2.00)
Immunomodulator therapy prior to infliximab therapy	26 (86.7)	23 (76.7)	0.32	1.97 (0.51-7.63)
Adalimumab therapy prior to infliximab therapy	4 (13.3)	0	0.12	10.30 (0.53-201.00)
Surgery prior to infliximab therapy	8 (26.7)	7 (23.3)	0.76	1.19 (0.37-3.85)

¹All patients received infliximab infusions at a standard protocol of 5 mg/kg at 0, 2, 6 and every 8 wk. IBD: Inflammatory bowel disease; CD: Crohn's disease; UC: Ulcerative colitis; GI: Gastro-intestinal.