Perianal disease, small bowel disease, smoking, prior steroid or early azathioprine/biological therapy are predictors of disease behavior change in patients with Crohn’s disease

Table 1 Clinical characteristics of patients with Crohn’s disease n (%)

	CD (n = 340)
Male/female	155/185
Age (yr)	38.1 ± 13.2
Age at presentation (yr)	28.7 ± 12.4
Duration (yr)	9.4 ± 7.5
Familial IBD	39 (11.4)
Location
L1	75
L2	99
L3	161
All L4	22
L4 only	5
Behavior at diagnosis
B1	198
B2	65
B3	77
Behavior change from B1 to B2/B3	61 (30.8)
Perianal disease	117 (34.4)
Frequent relapse	126 (37.1)
Arthritis	127 (37.5)
PSC	10 (2.9)
Ocular	17 (5.0)
Cutaneous	43 (12.6)
Steroid use	264 (77.6)
Azathioprine use	216 (63.5)
Azathioprine intolerance	36 (14.3)
Biological use	71 (20.9)
Surgery/reoperation	158 (46.5)/52 (32.8)
Smoking habits
No	151
Ex	36
Yes	153

L1: Ileal; L2: Colonic; L3: Ileocolonic; L4: Upper gastrointestinal disease; B1: Inflammatory; B2: Stenosing; B3: Penetrating disease behavior. IBD: Inflammatory bowel disease.

Table 2 Clinical factors associated with behavior change from inflammatory to complicated disease behavior n (%)

Factor	Prevalence without behavior change	Prevalence with behavior change	P-value	OR	95% CI
Disease location
L1	19 (13.9)	17 (27.9)
L2	55 (40.1)	18 (29.5)	0.04	-	-
L3	63 (46)	25 (41)
L4	0	1 (1.6)
Perianal disease	30 (22.2)	30 (49.2)	< 0.001	3.4	1.78-6.46
Frequent relapses	18 (13.1)	19 (31.1)	0.003	3.0	1.43-6.23
Disease duration (> 10 yr)	28 (20.4)	35 (57.4)	< 0.001	5.3	2.7-10.1
Smoking	51 (37.2)	32 (52.5)	0.04	1.9	1.02-3.45
Steroid use	106 (77.4)	59 (96.7)	0.001	8.6	2.00-37.3
Early azathioprine use	79 (57.7)	24 (39.3)	0.017	0.48	0.26-0.88
Early azathioprine/biological use	83 (60.6)	25 (41)	0.01	0.45	0.24-0.84
Need for operation	19 (13.9)	37 (60.7)	< 0.001	9.6	4.72-19.4

Table 3 Logistic regression: predictive factors for behavior change from non-stricturing, non-penetrating to complicated disease behavior in Crohn’s disease

Factor	Coefficient	P-value	OR	95% CI
Disease location	-0.385	0.13	-	-
Longer disease duration (≤ 10 yr vs > 10 yr)	1.476	< 0.001	4.37	2.04-9.38
Perianal disease	1.351	0.001	3.86	1.72-8.67
Frequent relapses	0.388	0.404	-	-
Smoking	1.015	0.009	2.76	1.29-5.89
Steroid use	2.089	0.01	8.07	1.64-39.7
Early azathioprine use	-1.055	0.006	0.35	0.16-074

The coefficient is equivalent to the natural log of the OR.

Table 4 Summary of Cox regression model: factors affecting time to disease behavior change

	P-value	Hazard ratio	95% CI
Disease location	0.001
L1	0.023	2.13	1.11-4.08
L2	0.05	0.54	0.27-1.001
L3	Reference
Perianal disease
Yes	< 0.001	3.26	1.90-5.59
No	Reference
Steroid use
Yes	0.006	7.48	1.79-31.2
No	Reference
Early azathioprine use
Yes	0.005	0.46	0.27-0.79
No	Reference
Smoking status
Yes	0.032	1.79	1.05-3.05
No	Reference