Clinical predictors of thiopurine-related adverse events in Crohn's disease

Table 1 Cohort demographics n (%)

Variables	Total(n = 351)	Discontinued due to adverse event(n = 110)	Continued therapy(n = 241)	P value
Gender				0.36
Female	185 (52.7)	62 (56.3)	123 (51.1)
Male	166 (47.3)	48 (43.6)	118 (48.9)
Age at diagnosis (A) (yr)				0.05
< 17	56 (16.0)	13 (11.8)	43 (17.8)
17-40	233 (66.4)	70 (63.3)	163 (67.6)
> 40	62 (17.7)	27 (24.5)	35 (14.5)
Age at thiopurine (yr)				0.007
< 17	21 (6.5)	5 (4.5)	16 (6.6)
17-40	195 (60.0)	44 (40.0)	151 (62.7)
> 40	109 (33.5)	43 (39.1)	66 (27.4)
L4 (upper gastrointestinal disease)				0.52
Yes	27 (7.7)	10 (9.1)	17 (7.1)
No	324 (92.3)	100 (90.1)	224 (92.9)
Behaviour (B) (%)				0.91
B1 (inflammatory)	183 (56.0)	55 (50.0)	128 (53.1)
B2 (fibrostenotic)	62 (19.0)	20 (18.2)	42 (17.4)
B3 (penetrating)	82 (25.1)	26 (23.6)	56 (23.2)
Perianal disease before thiopurine				0.69
Yes	82 (23.4)	24 (21.8)	58 (24.1)
No	269 (76.6)	86 (78.2)	183 (75.9)
Corticosteroid at diagnosis				0.35
Yes	142 (52.8)	39 (35.5)	103 (42.7)
No	127 (47.2)	42 (38.2)	85 (35.3)
Pre-thiopurine intestinal resection				0.81
Yes	140 (39.9)	45 (40.9)	95 (39.4)
No	211 (60.1)	65 (59.1)	146 (60.6)
Disease duration before thiopurines (yr)				0.22
< 1	100 (30.8)	22 (20.0)	78 (32.4)
1-5	81 (24.9)	22 (20.0)	59 (24.5)
5-10	63 (19.4)	23 (20.9)	40 (16.6)
> 10	81 (24.9)	25 (22.7)	56 (23.2)
5-ASA exposure before thiopurine	66 (24.8)	18 (16.4)	48 (19.9)	0.47
Anti-TNFα exposure1				< 0.0001
Thiopurine monotherapy	234 (66.7)	97 (88.2)	137 (56.9)
Non-con. Comb. therapy	79 (22.5)	5 (4.5)	74 (30.7)
Con. Comb therapy	38 (10.8)	8 (7.3)	30 (12.4)
Smoking history				0.12
Never	180 (51.3)	48 (43.6)	132 (54.8)
History of smoking	126 (35.9)	49 (44.5)	77 (32.0)
Unknown	45 (12.8)	13 (11.8)	32 (13.2)

¹Thiopurine monotherapy, defined as patients naive to anti-TNF therapy or suffering an adverse event that led to discontinuation of the thiopurine prior to exposure to anti-TNF therapy; non-concomitant onset combination therapy defined as anti-TNF therapy started more than 3 mo after thiopurine onset; concomitant onset combination therapy defined as concomitant prescription of thiopurine and anti-TNF within 3 mo. Clinical characteristics of the 351 CD patients treated with a thiopurine stratified by an adverse event requiring withdrawal of thiopurines. Anti-TNF: Anti-tumour necrosis factor; ASA: Aminosalicylic acid; CD: Crohn's disease.