Location-based prediction model for Crohn’s disease regarding a novel serological marker, anti-chitinase 3-like 1 autoantibodies

Table 1 Clinical characteristics of inflammatory bowel disease patients, n (%)

	CD (n = 266)	UC (n = 187)
Age at presentation (yr), median (IQR)	25 (19-33)	33 (23-43)
Male/female (n)	112/154	86/101
Follow-up (mo) from, median (IQR)
Diagnosis1	143 (99-214)	135 (84-213)
Time of serum collection, median (IQR)	97 (77-118)	78 (51-102)
Location/extent at diagnosis
L1	58 (21.8%)	E1 30 (16.0%)
L2	86 (32.3%)	E2 104 (55.6%)
L3	121 (45.5%)	E3 53 (28.3%)
L4 only	1 (0.4%)
Behavior at diagnosis/last follow up
B1	213 (80.1%)/117 (44.8%)
B2	32 (12.0%)/54 (20.7%)
B3	21 (7.9%)/90 (34.5%)
Perianal disease
At diagnosis/last follow-up1	48 (18.0%)/100 (38.3%)
Extraintestinal manifestations
PSC	8 (3.0%)	8 (4.3%)
Arthritis	49 (18.4%)	26 (13.9%)
Skin	35 (13.2%)	16 (8.6%)
Ocular	65 (24.4%)	12 (6.4%)
Smoking habits
Never	215 (80.8%)	167 (89.3%)
Yes	46 (17.3%)	18 (9.6%)
Previous	5 (1.9%)	2 (1.1%)
Familial IBD	12 (4.4%)	6 (3.2%)
Frequent relapse	52 (20.9%)
Cumulative exposure of medication and surgeries during follow-up
Steroid use/refractory	219 (82.3%)/30 (13.7%)	117 (63.9%)/11 (7.6%)
Azathioprine use	198 (74.4%)	70 (38.3%)
Biological use	112 (42.1%)	25 (13.4%)
Resective surgery/multiple in CD	117 (44.8%)/ 33 (12.6%)
Colectomy in UC		11 (6.0%)
Surgery due to perianal complication/multiple	61 (23.4%)/33 (12.6%)

¹261 Crohn’s disease and 183 ulcerative colitis patients had follow-up.

Location: L1: Ileal, L2: Colonic, L3: Ileocolonic, L4: Upper gastrointestinal disease. Behavior: B1: Inflammatory (non stricturing/non penetrating), B2: Stenosing (stricturing), B3: Penetrating. Disease extent: E1: Proctitis; E2: Left sided colitis; E3: Extensive colitis. Surgery: Crohn’s disease-related abdominal surgery and colectomy in ulcerative colitis. CD: Crohn’s disease; IQR: Interquartile range; UC: Ulcerative colitis; PSC: Primary sclerosing cholangitis; IBD: Inflammatory bowel disease.

Table 2 Prevalence of autoantibodies against chitinase 3-like 1 in inflammatory bowel disease patients

Serum aCHI3L1	CD (n = 257)		UC (n = 180)		HCONT (n = 86)
	n	%	n	%	n	%
IgG	21	8.2%b	3	1.7%b	2	2.83%
IgA	75	29.2%a,c	20	11.1%c,d	2	2.83%a,d
sIgA	101	39.3%a	59	32.8%e	4	4.65%a,e

^aP ≤ 0.0001. Crohn’s disease vs controls.

^bP = 0.003. Crohn’s disease vs ulcerative colitis.

^cP ≤ 0.0001. Crohn’s disease vs ulcerative colitis.

^dP = 0.016. Ulcerative colitis vs controls.

^eP ≤ 0.0001. Ulcerative colitis vs controls.

Using χ²-test with Yates correction. CD: Crohn’s disease; UC: Ulcerative colitis; IgA: Immunoglobulin A; sIgA: Secretory immunoglobulin A; aCHI3L1: Anti-chitinase 3-like 1 autoantibodies; HCONT: Healthy controls.

Table 3 Stability of anti-chitinase 3-like 1 autoantibodies status over time in patients with Crohn’s disease during the disease course

Serologic antibodies	(Sub)type	n	Stable negative, n (%)	Stable positive, n (%)	Negative to positive, n (%)	Positive to negative, n (%)
aCHI3L1	IgG	165	152 (92.1)	2 (1.2)	2 (1.2)	9 (5.5)
	IgA	165	92 (55.8)	39 (23.6)	17 (10.3)	17 (10.3)
	sIgA	165	83 (50.3)	51 (30.9)	14 (8.5)	17 (1.1)

aCHI3L1: Anti-chitinase 3-like 1 autoantibodies.

Table 4 Association of anti-chitinase 3-like 1 autoantibodies antibody formation with clinical, serological, and genetic characteristics of Crohn’s disease at diagnosis and last follow-up

Anti-CHI3L1	IgA		sIgA
	OR (95%CI)	P value	OR (95%CI)	P value
At diagnosis
Complicated disease behaviour	1.86 (0.97-3.55)	0.081	2.37 (1.26-4.48)	0.009
Colon involvement	6.61 (2.29-19.07)	< 0.0001	2.09 (1.07-4.10)	0.038
ASCA IgA	4.11 (2.24-7.55)	< 0.0001	4.16 (2.40-7.19)	< 0.0001
OMP IgA	3.16 (1.79-5.57)	< 0.0001	2.64 (1.57-4.44)	< 0.0001
Anti-PS/PT IgA	3.46 (1.49-8.04)	0.005	2.56 (2.15-14.58)	< 0.0001
Anti-GP2 IgA	4.76 (0.87-26.18)	0.108	9.47 (1.12-79.52)	0.018
At last visit
Frequent relapse	2.56 (1.34-4.91)	0.005	1.89 (1.00-3.56)	0.047

Column corresponding to immunoglobulin G type anti-chitinase 3-like 1 autoantibodies and rows corresponding to age at onset, perianal disease at diagnosis, extraintestinal manifestations, NOD2/CARD15 mutations and therapy were omitted because statistically significant differences for a given parameter were not obtained. Positive associations are indicated in bold and negative associations are in italics (P values, odds ratio and 95% confidence interval). IgA: Immunoglobulin A; sIgA: Secretory immunoglobulin A; aCHI3L1: Anti-chitinase 3-like 1 autoantibodies; OR: Odds ratio; CI: Confidence interval; ASCA: Anti-Saccharomyces cerevisiae antibody; OMP: Outer membrane protein; Anti-PS/PT: Anti-phosphatidylserine/prothrombin antibody; Anti-GP2: Anti-glycoprotein 2 antibody.

Table 5 Univariate and multivariate Cox regression analyses evaluating the association between clinical and serologic variables and the study end-point events (complicated disease course) in Crohn’s disease patients. Subgroup analysis of B1 patients with colonic involvement is shown in the second half of the table

		Development of internal penetrating and/or stenotic complication in B1 patients at diagnosis							Development of internal penetrating and/or stenotic complication in B1 patients at diagnosis with colonic involvement
		n of subjects	CP of event (%)1	pLogRank	HR (95%CI)2	P value2	HR (95%CI)3	P value3	n of subjects	CP of event (%)1	pLogRank	HR (95%CI)2	P value2	HR (95%CI)3	P value3
Overall population		209	47.5						160	44.4
Clinical factors
Age at onset	A1	27	47.7	0.137	1.95 (0.74-5.14)	0.175			26	47.7	0.095	4.12 (0.93-18.28)	0.062	7.26 (0.94-55.89)	0.057
	A2	157	51.0		2.26 (0.98-5.21)	0.055			118	46.7		4.20 (1.02-17.23)	0.046	7.79 (1.07-56.52)	0.042
	A3	25	25.9			0.152			16	19.8			0.137		0.127
Gender	Male	91	47.7	0.494	1.15 (0.77-1.74)	0.495			69	44.8	0.489	1.18 (0.74-1.90)	0.490	1.10 (0.68-1.79)	0.697
	Female	118	47.3						91	43.9
Location	L1 + L3	129	57.3	0.002	1.98 (1.27-3.08)	0.003			80	55.5	0.013	1.82 (1.13-2.95)	0.014	1.83 (1.12-2.99)	0.016
	L2	80	34.5						80	34.5
	L2 + L3	160	44.4	0.027	0.59 (0.37-0.95)	0.029
	L1	49	62.9
Frequent relapse	No	154	44.8						115	41.7
	Yes	45	53.3	0.489	1.18 (0.74-1.89)	0.490			38	52.7	0.533	1.19 (0.69-2.04)	0.534
Antibodies against CHI3L1
aCHI3L1 IgG	Negative	182	49.7						141	45.5
	Positive	17	33.9	0.219	0.57 (0.23-1.41)	0.226			14	38.6	0.561	0.76 (0.31-1.90)	0.562
aCHI3L1 IgA	Negative	145	44.1						103	37.4
	Positive	54	58.3	0.076	1.49 (0.96-2.31)	0.078			52	58.8	0.028	1.71 (1.05-2.78)	0.030	1.67 (1.02-2.71)	0.041
aCHI3L1 sIgA	Negative	127	43.7						92	36.6
	Positive	72	55.7	0.057	1.50 (0.99-2.29)	0.059			63	56.6	0.028	1.70 (1.05-2.75)	0.031	1.59 (0.98-2.58)	0.061

¹Cumulative probability of event (%) corresponds to the median follow-up values.

²Univariate analysis.

³Multivariate analysis.

Rows corresponding to perianal disease according to the Montreal classification at diagnosis, smoking habits, and familial inflammatory bowel diseases were omitted because statistically significant differences for a given parameter were not obtained. HR: Hazard ratio; Age at onset: A1: ≤ 16 years, A2: 17-40 years, A3: > 40 years; Location: L1: Ileal, L2: Colonic, L3: Ileocolonic, L1 + L3: Ileal involvement, L2 + L3: Colonic involvement; Behavior: B1: Inflammatory/non-stricturing and non-penetrating; B2: Stenosing; B3: Internal penetrating; P0: Lack of perianal disease/involvement; P1: Perianal disease/involvement. IBD: Inflammatory bowel diseases; Ig: Immunoglobulin; sIgA: Secretory IgA; aCHI3L1: Anti-chitinase 3-like 1 autoantibodies; CP: Cumulative probability; CI: Confidence interval; HR: Hazard ratio.

Table 6 Univariate and multivariate Cox regression analyses evaluating the association between clinical and serologic variables and the study end-point events (development of perianal complications) in Crohn’s disease patients. Subgroup analysis of B1 patients with colonic involvement is shown in the second half of the table

		Development of perianal penetrating complication in P0 patients at diagnosis							Development of perianal penetrating complication in P0 patients at diagnosis with colonic involvement
		n of subjects	CP of event (%)1	pLogRank	HR (95%CI)2	P value2	HR (95%CI)3	P value3	n of subjects	CP of event (%)1	pLogRank	HR (95%CI)2	P value2	HR (95%CI)3	P value3
Overall population		215	24						157	27.9
Clinical factors
Age at onset	A1	25	34.9	0.011	5.05 (1.44-17.7)	0.012			24	34.9	0.109	3.22 (0.92-11.31)	0.068
	A2	158	23.9		2.46 (0.76-8.01)	0.134			113	28.5		1.94 (0.59-6.33)	0.274
	A3	30	7			0.016			20	10.5			0.122
Gender	Male	90	23.1	0.584	0.85 (0.48-1.51)	0.585			68	27.2	0.474	0.81 (0.45-1.45)	0.475
	Female	123	24						89	28.7
Location	L1 + L3	147	20.5	0.066	0.60 (0.35-1.04)	0.640			91	27.1	0.634	0.87 (0.49-1.54)	0.635
	L2	66	28.8						66	28.8
	L2 + L3	157	27.9	0.002	4.25 (1.53-11.79)	0.001
	L1	56	8.9
Frequent relapse	No	160	18						115	22.3
	Yes	45	40.9	0.000	2.94 (1.68-5.15)	0.000			33	44.2	0.001	2.61 (1.45-4.68)	0.001
Antibodies against CHI3L1
aCHI3L1 IgG	Negative	187	22.3						138	25.0
	Positive	15	33.3	0.988	0.99 (0.36-2.76)	0.988			12	37.5	0.933	0.96 (0.34-2.68)	0.933
aCHI3L1 IgA	Negative	145	21.7						96	25.2
	Positive	57	25.8	0.624	1.16 (0.64-2.11)	0.624			54	26.7	0.862	0.95 (0.51-1.75)	0.862
aCHI3L1 sIgA	Negative	122	22.0						83	24.9
	Positive	80	24.7	0.746	0.91 (0.51-1.62)	0.746			67	27.6	0.645	0.87 (0.48-1.58)	0.645

¹Cumulative probability of event (%) corresponds to the median follow-up values.

²Univariate analysis.

³Multivariate analysis.

Rows corresponding to behaviour according to the Montreal classification at diagnosis, smoking habits, and familial inflammatory bowel disease were omitted because statistically significant differences for a given parameter were not obtained. HR: Hazard ratio; Age at onset: A1: ≤ 16 years, A2: 17-40 years, A3: > 40 years; Location: L1: Ileal, L2: Colonic, L3: Ileocolonic, L1 + L3: Ileal involvement, L2 + L3: Colonic involvement; Behavior: B1: Inflammatory/non-stricturing and non-penetrating; B2: Stenosing; B3: Internal penetrating; P0: Lack of perianal disease/involvement; P1: Perianal disease/involvement. IBD: Inflammatory bowel diseases; Ig: Immunoglobulin; sIgA: Secretory IgA; aCHI3L1: Anti-chitinase 3-like 1 autoantibodies; CP: Cumulative probability; CI: Confidence interval; HR: Hazard ratio.

Table 7 Univariate and multivariate Cox regression analyses evaluating the association between clinical and serologic variables and the study end-point events (need for resective surgery) in Crohn’s disease patients. Subgroup analysis of B1 patients with colonic involvement is shown in the second half of the table

		Need for resective surgery in B1 patients at diagnosis							Need for resective surgery in B1 patients at diagnosis with colonic involvement
		n of subjects	CP of event (%)1	pLogRank	HR (95%CI)2	P value2	HR (95%CI)3	P value3	n of subjects	CP of event (%)1	pLogRank	HR (95%CI)2	P value2	HR (95%CI)3	P value3
Overall population		209	38						160	36
Clinical factors
Age at onset	A1	27	29.1	0.937	0.94 (0.38-2.35)	0.896			26	29.1	0.989	0.96 (0.33-2.80)	0.945
	A2	157	39.8		1.06 (0.50-2.22)	0.887			118	37		1.01 (0.40-2.58)	0.980
	A3	25	40.4			0.937			16	43			0.989
Gender	Male	91	34.2	0.958	0.99 (0.62-1.57)	0.958			69	33.7	0.977	0.99 (0.59-1.66)	0.977
	Female	118	40.8						91	37.7
Location	L1 + L3	129	31.1	0.109	1.48 (0.91-2.40)	0.112			80	41.5	0.174	1.45 (0.85-2.43)	0.176
	L2	80	43.7						80	31.1
	L2 + L3	160	50.2	0.382	0.78 (0.44-1.38)	0.384
	L1	49	36.0
Frequent relapse	No	154	36.9	0.950					115	35.8
	Yes	45	38.7		0.98 (0.58-1.68)	0.950			38	32.4	0.602	0.85 (0.47-1.56)	0.852
Antibodies against CHI3L1
aCHI3L1 IgG	Negative	182	38.9						141	36.4
	Positive	17	34.7	0.997	1.00 (0.43-2.32)	0.997			14	39.9	0.623	1.24 (0.53-2.89)	0.624
aCHI3L1 IgA	Negative	145	34.1						103	30.3
	Positive	54	48.5	0.246	1.34 (0.82-2.18)	0.248			52	47.6	0.255	1.36 (0.80-2.29)	0.257
aCHI3L1 sIgA	Negative	127	33.8						92	29.8
	Positive	72	46.3	0.159	1.40 (0.88-2.24)	0.161			63	46.4	0.227	1.37 (0.82-2.31)	0.230

¹Cumulative probability of event (%) corresponds to the median follow-up values.

²Univariate analysis.

³Multivariate analysis.

Rows corresponding to perianal disease according to the Montreal classification at diagnosis, smoking habits, and familial inflammatory bowel diseases were omitted because statistically significant differences for a given parameter were not obtained. HR: Hazard ratio; Age at onset: A1: ≤ 16 years, A2: 17-40 years, A3: > 40 years; Location: L1: Ileal, L2: Colonic, L3: Ileocolonic, L1 + L3: Ileal involvement, L2 + L3: Colonic involvement; Behavior: B1: Inflammatory/non-stricturing and non-penetrating; B2: Stenosing; B3: Internal penetrating; P0: Lack of perianal disease/involvement; P1: Perianal disease/involvement. IBD: Inflammatory bowel diseases; Ig: Immunoglobulin; sIgA: Secretory IgA; aCHI3L1: Anti-chitinase 3-like 1 autoantibodies; CP: Cumulative probability; CI: Confidence interval; HR: Hazard ratio.

Table 8 Univariate and multivariate Cox regression analyses evaluating the association between clinical and serologic variables and the study end-point events (reoperation after resection) in Crohn’s disease patients. Subgroup analysis of B1 patients with colonic involvement is shown in the second half of the table

		Need for resective surgery in B1 patients with previous CD-related abdominal surgery							Need for resective surgery in B1 patients with previous CD-related abdominal surgery and colonic involvement
		n of subjects	CP of event (%)1	pLogRank	HR (95%CI)2	P value2	HR (95%CI)3	P value3	n of subjects	CP of event (%)1	pLogRank	HR (95%CI)2	P value2	HR (95%CI)3	P value3
Overall population		73	28.2						58	26.6
Clinical factors
Age at onset	A1	11	60.2	0.186	4.47 (0.52-38.57)	0.173			11	60.2	0.122	3.16 (0.36-27.59)	0.298
	A2	54	23.8		1.94 (0.25-15.25)	0.530			42	17.9		0.97 (0.12-8.13)	0.976
	A3	8	12.5			0.214			5	20.0			0.150
Gender	Male	32	29.5		1.03 (0.38-2.77)	0.956			26	19.8	0.368	0.58 (0.17-1.93)	0.374
	Female	41	28.4	0.956					32	33.2
Location	L1 + L3	45	31.0	0.339	1.67 (0.58-4.82)	0.345			30	29.5	0.454	1.55 (0.49-4.92)	0.457
	L2	28	23.2						28	23.2
	L2 + L3	58	26.6	0.430	0.64 (0.20-1.98)	0.434
	L1	15	35.8
Familial IBD	No	68	25.5						55	23.8
	Yes	5	60.0	0.010	4.59 (1.29-16.36)	0.019			3	66.7	0.002	8.19 (1.64-40.86)	0.010
Frequent relapse	No	51	14.9						40	9.0
	Yes	19	61.0	0.006	3.79 (1.36-10.55)	0.011			15	73.3	0.000	7.94 (2.03-31.00)	0.003
Antibodies against CHI3L1
aCHI3L1 IgG	Negative	64	27.3						51	23.7
	Positive	4	40.0	0.595	1.50 (0.34-6.69)	0.597			6	40.0	0.485	1.72 (0.37-8.04)	0.490
aCHI3L1 IgA	Negative	46	21.5						34	16.3
	Positive	24	42.1	0.238	1.83 (0.66-5.04)	0.245			23	39.3	0.220	2.07 (0.63-6.80)	0.230
aCHI3L1 sIgA	Negative	40	17.2						31	13.9
	Positive	30	46.2	0.052	2.68 (0.95-7.58)	0.062			26	41.0	0.086	2.82 (0.82-9.68)	0.100

¹Cumulative probability of event (%) corresponds to the median follow-up values.

²Univariate analysis.

³Multivariate analysis.

Rows corresponding to perianal disease according to the Montreal classification at diagnosis, smoking habits were omitted because statistically significant differences for a given parameter were not obtained. HR: Hazard ratio; Age at onset: A1: ≤ 16 years, A2: 17-40 years, A3: > 40 years; Location: L1: Ileal, L2: Colonic, L3: Ileocolonic, L1 + L3: Ileal involvement, L2 + L3: Colonic involvement; Behavior: B1: Inflammatory/non-stricturing and non-penetrating; B2: Stenosing; B3: Internal penetrating; P0: Lack of perianal disease/involvement; P1: Perianal disease/involvement. IBD: Inflammatory bowel diseases; Ig: Immunoglobulin; sIgA: Secretory IgA; aCHI3L1: Anti-chitinase 3-like 1 autoantibodies; CP: Cumulative probability; CI: Confidence interval; HR: Hazard ratio.