Azathioprine monotherapy withdrawal in inflammatory bowel diseases: A retrospective mono-centric study

Table 1 Demographic and clinical characteristics of the studied population stratified according to disease type

Characteristic	Crohn's disease	Ulcerative colitis	P value
Included patients	141	133
Sex, % males	54.6%	59.4%	0.42
Mean age at IBD diagnosis in yr	33.2 ± 14.2	28.8 ± 14.4	0.01
Disease location
Upper GI-L4	5.7%
Small bowel-L1	17.8%
Ileum + colon-L3	61%
Pancolitis-L2	15.6%	61%
Left-sided colitis		37.5%
Proctosigmoiditis		1.5%
Perianal	7.8%
Phenotype
Inflammatory	56.7%
Stenosing	24.8%
Fistulizing	7.8%
Fistulizing + Stenosing	5.7%
Inflammatory + Fistulizing	2.2%
Inflammatory + Stenosing	2.8%
Reasons for AZA introduction			0.23
Steroid-dependent	95.8%	90.2%
Steroid-refractory	2.1%	5.3%
Steroid intolerance	0.7%	3%
Other reasons	1.4%	1.5%
Comorbidities
PSC	0%	2.3%	0.07
Autoimmune rheumatic diseases	7.8%	3.0%	0.08
Cardiac involvement	4.3%	7.5%	0.25

AZA: Azathioprine; IBD: Inflammatory bowel disease; PSC: Primary sclerosing cholangitis.

Table 2 Reasons for discontinuation of azathioprine treatment

Reason for discontinuation	Patients, n	% of 274 total
Inefficacy	44	16.1
Relapse	37	13.5
Remission	69	25.2
Pancreatitis or isolated raised in amylase/lipase or ALT > 2×ULN	48	17.5
Leukopenia	23	8.4
Infections	13	4.5
Unspecified intolerance	9	3.3
Nausea/vomiting	15	5.5
Neoplasia	3	1.1
Asthenia	2	0.7
Pregnancy desire	4	1.4
Surgery not associated with IBD	2	0.7
Unspecific patient voluntary	5	2.1

IBD: Inflammatory bowel disease.

Table 3 Incidence rates and unadjusted and adjusted hazard ratios of disease relapse in the overall population and different subgroups

Group or subgroup	Events	Rate per 10 person-yr (95%CI)	HR (95%CI)	Adjusted HR (95%CI)
Entire population	141	1.4 (1.2-1.7)
UC	64	1.4 (1.1-1.7)	1
CD	77	1.5 (1.2-1.8)	1.16 (0.8-1.6)
Males	85	1.7 (1.4-2.1)	1
Females	56	1.2 (0.9-1.5)	0.76 (0.5-1.1)
Age ≤ 35 yr	62	1.9 (1.4-2.4)	1
Age > 35 yr	79	1.2 (0.9-1.5)	0.69 (0.5-0.9)
Active patients	66	7.0 (5.5-8.9)	1	1
Patients in remission	21	0.7 (0.4-1.0)	0.17 (0.1-0.3)	0.17 (0.1-0.3)
Other groups	54	0.9 (0.7-1.2)	0.25 (0.2-0.4)	0.26 (0.1-0.4)

CD: Crohn's disease; CI: Confidence interval; HR: Hazard ratios; UC: Ulcerative colitis.