Development and validation of a model to determine risk of refractory benign esophageal strictures

Table 1 Characteristics of 507 patients with benign esophageal strictures

Category		N (%) / M (range) n = 507
Sex	Female	178 (35.1)
	Male	329 (64.9)
Age (yr)	-	58 (16-88)
Etiology1	Post-ESD/ESTD	78 (15.4)
	Achalasia	148 (29.2)
	Caustic	13 (2.6)
	Postoperative	246 (48.5)
	Peptic	3 (0.6)
	Trauma	2 (0.4)
	Mixed	2 (0.4)
	Post-radiation	1 (0.2)
	Iatrogenic	14 (2.8)
Location of strictures1	Cervical	40 (7.9)
	Thoracic	315 (62.1)
	Ventral	152 (30.0)
Number of strictures	One	477 (94.1)
	Two	24 (4.7)
	Three or more	6 (1.2)
Length of strictures (cm)	-	0.5 (0.5, 10)
Times	One	299 (59.0)
	Two	85 (16.8)
	Three	42 (8.3)
	Four	24 (4.7)
	Five or more	57 (11.2)
Endoscopic therapy	Stenting + dilation	55 (10.8)
	Dilation only	452 (89.2)

¹Fisher’s exact test. The mixed etiology was the patients with refractory benign esophageal strictures caused by caustic injury and esophageal anastomosis following colon surgery. ESD: Endoscopic submucosal dissection; ESTD: Endoscopic submucosal tunnel dissection.

Table 2 Univariate and multivariate analyses of refractory benign esophageal strictures

Category		Non-RBES n (%) / M (range) n = 450	RBES n (%) / M (range) n = 57	P1	P2	OR (95%CI)
Sex	Female	160 (89.9)	18 (10.1)	0.553	0.665	0.916 (0.617-1.361)
	Male	290 (88.1)	39 (11.9)		0.665	1.091 (0.735-1.620)
Age (yr)	-	58 (16, 88)	60 (16, 75)	0.548	0.034	0.968 (0.939-0.998)
Etiology	Post-ESD/ESTD	55 (70.5)	23 (29.5)	< 0.001	0.007	5.874 (1.623-21.255)
	Postoperative	223 (90.7)	23 (9.3)		0.009	3.333 (1.358-8.182)
	Achalasia	147 (99.3)	1 (0.3)		0.013	0.084 (0.012-0.597)
	Caustic	5 (38.5)	8 (61.5)		0.320	1.512 (0.67-3.413)
	Other	20 (90.9)	2 (9.1)		0.208	0.404 (0.099-1.653)
Location of strictures	Cervical	30 (75.0)	10 (25.0)	< 0.001	0.603	1.250 (0.539-2.901)
	Thoracic	271 (86.0)	44 (14.0)		0.671	0.869 (0.454-1.663)
	Ventral	149 (98.0)	3 (2.0)		0.884	0.921 (0.303-2.794)
Length of strictures (cm)		0.5 (0.5, 8)	2 (0.5, 10)	< 0.001	0.001	1.344 (1.135-1.591)
Number of strictures	One	436 (91.4)	41 (8.6)	< 0.001	0.049	0.615 (0.370-1.023)
	Two or more	14 (46.7)	16 (53.3)		0.049	1.625 (0.977-2.704)
Endoscopic therapy	Dilation only	411 (90.9)	41 (9.1)	< 0.001	0.009	0.582 (0.388-0.874)
	Stenting + dilation	39 (70.9)	16 (29.1)		0.009	1.718 (1.145-2.577)

RBES: Refractory benign esophageal strictures; ESD: Endoscopic submucosal dissection; ESTD: Endoscopic submucosal tunnel dissection.

Table 3 Characteristics for included patients in development and validation cohorts

Category	Development cohort (n = 345)	Validation cohort (n = 162)	All (n = 507)
Sex
Female	119	59	178
Male	226	103	329
Age (yr)
50 ≤ n < 70	197	83	280
<50	103	55	158
≥70	45	24	69
Etiology
Achalasia	103	45	148
Post-ESD/ESTD	58	20	78
Postoperative	170	76	246
Caustic	6	7	13
Other	8	14	22
Location of strictures
Cervical	26	14	40
Thoracic	208	107	315
Ventral	111	41	152
Length of strictures (cm)
<2 cm	282	135	417
≥2 cm	63	27	90
Number of strictures
One	325	152	477
Two or more	20	10	30

ESD: Endoscopic submucosal dissection; ESTD: Endoscopic submucosal tunnel dissection.

Table 4 Development of a 9-point risk-scoring model to predict refractory benign esophageal strictures

Factor	P	OR	Beta coefficient	Score
Age (yr)
50 ≤ n < 70	0.066	1 (Ref.)	0	0
<50	0.021	1.2-8.6	1.2	1
≥70	0.776	0.4-3.2	0.1	0
Etiology
Achalasia	0.037	1 (Ref.)	0	0
Post-ESD/ESTD	0.004	25.8 (2.9-230.5)	3.3	3
Caustic	0.009	52.3 (2.7-1027.8)	4.0	4
Postoperative	0.006	19.2 (2.3-161.2)	3.0	3
Other	0.216	6.7 (0.3-136.6)	1.9	2
Number of strictures
One	0.042	1 (Ref.)	0	0
Two or more	0.042	3.5 (1.1-11.5)	1.2	1
Length of strictures (cm)
< 2 cm	< 0.001	1 (Ref.)	0	0
≥ 2 cm	< 0.001	6.4 (2.7-15.2)	1.9	2

RBES: Refractory benign esophageal strictures; ESD: Endoscopic submucosal dissection; ESTD: Endoscopic submucosal tunnel dissection.

Table 5 Risk score and proportion of refractory benign esophageal strictures in esophageal strictures

Risk score	Rate of RBES (n = 345)	Rate of RBES (n = 162)	Risk	Point	Development cohort Rate of RBES	Validation cohort Rate of RBES
0	2.6% (1/38)	0% (0/11)	Low	0-2	1.0% (1/107)	0% (0/43)
1	0% (0/67)	0% (0/28)	Intermediate	3-5	12.2% (26/213)	7.3% (8/110)
2	0% (0/2)	0% (0/4)	High	6-8	76.0% (19/25)	33.3% (3/9)
3	6.7% (10/149)	6% (5/84)
4	14.3% (4/28)	0% (0/8)
5	33.3% (12/36)	16.7% (3/18)
6	73.7% (14/19)	14.3% (1/7)
7	100% (3/3)	100% (1/1)
8	66.7% (2/3)	100% (1/1)

RBES: Refractory benign esophageal strictures.

Table 6 Adverse events in patients with refractory benign esophageal strictures , n (%)

	Early, n = 3	Late, n = 11
Stent overgrowth	0	2
Stent migration	0	5
Food impaction	0	3
Fistula	1	5
Bleeding	1	0
Intolerable chest pain	1	0

Table 7 Characteristics of 57 patients with refractory benign esophageal strictures

Category	N (%) / M (range)	Success (n = 27)	Failure (n = 30)	P
Sex
Female	18 (31.5%)	9	9	0.787
Male	39 (68.5%)	18	21
Age (yr)	60 (16-75)	58 (16-75)	60.5 (16-74)	0.472
Etiology
Post-ESD/ESTD	23 (40.4%)	11	12	0.003
Postoperative	23 (40.4%)	7	16
Caustic	8 (14%)	8	0
Other*	3 (5.2%)	1	2
Location of strictures
Cervical	10 (17.5%)	5	5	0.135
Thoracic	44 (77.2%)	22	22
Ventral	3 (5.3%)	0	3
Number of strictures
1	41 (71.9%)	16	25	0.351
2	11 (19.3%)	7	4
3 and more	5 (8.8%)	4	1
Length of strictures (cm)	2 (0.5-10)	3 (0.5-10)	2 (0.5-10)	0.105
Diameter of strictures (mm)	4 (1-8.5)	4 (1-8.5)	4 (0.5-8.5)	0.240
Times	7 (5-28)	6 (5-19)	7.5 (5-28)	0.129
Endoscopic therapy
Stenting + dilation	16 (28%)	6	10	0.043
Dilation only	41 (72%)	21	20

RBES: Refractory benign esophageal strictures; ESD: Endoscopic submucosal dissection; ESTD: Endoscopic submucosal tunnel dissection.