Narrow-band imaging-modified Kyoto score predicts pathological upgrading after endoscopic submucosal dissection in gastric intraepithelial neoplasia

Table 1 Components of both the conventional and narrow-band imaging-modified Kyoto classification scores

Component	Conventional score	NBI-modified score	Scoring range
Atrophy	0 = none or closed-type (C1); 1 = closed-type (C2 or C3); 2 = open-type (O1-O3)	Same as the conventional Kyoto score	0-2
Intestinal metaplasia	0 = none; 1 = confined to the antrum; 2 = extending to the corpus	IM identified by LBC, WOS, and/or tubulovillous or villous microsurface patterns under NBI-ME: 0 = none; 1 = focal involvement (≤ 30%); 2 = extensive involvement (> 30%)	0-2
Diffuse redness	0 = absent diffuse redness with clearly visible RAC; 1 = mild diffuse redness with partially visible or blurred RAC; 2 = severe diffuse redness with absent or invisible RAC	Same as the conventional Kyoto score	0-2
Enlarged folds	0 = < 5 mm; 1 = ≥ 5 mm	Same as the conventional Kyoto score	0-1
Nodularity	0 = absent; 1 = present	Same as the conventional Kyoto score	0-1
Total score	8	8	0-8

In the narrow-band imaging-modified Kyoto score, only the intestinal metaplasia component was modified using narrow-band imaging magnifying endoscopy-based assessment; the other four components retained the original Kyoto classification criteria. The 30% threshold for grading the extent of intestinal metaplasia followed the convention established by the Endoscopic Grading of Gastric Intestinal Metaplasia system. NBI: Narrow-band imaging; IM: Intestinal metaplasia; LBC: Light blue crest; WOS: White opaque substance; NBI-ME: Narrow-band imaging magnifying endoscopy; RAC: Regular arrangement of collecting venules.

Table 2 Baseline characteristics of patients stratified by pathological upgrading status, n (%)/mean ± SD

Characteristic		Upgrading group (n = 92)	Non-upgrading group (n = 133)	χ2/t	P value
Age, years	< 40	16 (17)	27 (20)	0.323	0.851
	40-60	31 (34)	42 (32)
	> 60	45 (49)	64 (48)
Sex	Male	48 (52)	62 (47)	0.672	0.412
	Female	44 (48)	71 (53)
BMI, kg/m2	< 18	9 (10)	11 (8)	0.196	0.907
	18-24	43 (47)	65 (49)
	> 24	40 (43)	57 (43)
Helicobacter pylori status	Current	55 (60)	59 (44)	5.174	0.023
	Past/never	37 (40)	74 (56)
Lesion size	< 20 mm	33 (36)	72 (54)	7.290	0.007
	≥ 20 mm	59 (64)	61 (46)
Lesion location	Antrum	41 (45)	78 (58)	4.335	0.114
	Angle	20 (22)	22 (17)
	Body/cardia	31 (33)	33 (25)
Macroscopic type (Paris)	0-IIa (elevated)	17 (19)	45 (34)	12.336	0.002
	0-IIb; 0-(flat)	26 (28)	47 (35)
	0-IIc (depressed)	49 (53)	41 (31)
Surface redness		59 (64)	54 (41)	12.041	< 0.001
Surface nodularity		47 (51)	56 (42)	1.767	0.184
Preoperative biopsy	LGIN	61 (66)	101 (76)	2.504	0.114
	HGIN	31 (34)	32 (24)
Conventional Kyoto score		4.62 ± 0.49	3.94 ± 0.64	8.632	< 0.001
Atrophy subscore		1.55 ± 0.50	1.47 ± 0.50	1.300	0.195
IM subscore (white-light)		1.72 ± 0.45	1.38 ± 0.49	5.325	< 0.001
Diffuse redness subscore		1.50 ± 0.50	1.41 ± 0.49	1.281	0.202
Enlarged folds subscore		0.37 ± 0.49	0.28 ± 0.45	1.450	0.148
Nodularity subscore		0.32 ± 0.47	0.29 ± 0.45	1.087	0.278
NBI-modified Kyoto score		5.21 ± 0.81	3.93 ± 0.64	13.173	< 0.001
NBI-IM subscore (0-2)		1.82 ± 0.39	1.44 ± 0.50	5.989	< 0.001

The χ² statistic and t statistic were obtained from the χ² test and independent-samples t-test, respectively. BMI: Body mass index; LGIN: Low-grade intraepithelial neoplasia; HGIN: High-grade intraepithelial neoplasia; IM: Intestinal metaplasia; NBI: Narrow-band imaging.

Table 3 Univariable and multivariable logistic regression analysis for pathological upgrading

Variable	Univariable analysis		Multivariable analysis
	OR (95%CI)	P value	OR (95%CI)	P value
Lesion size ≥ 20 mm	2.110 (1.223-3.642)	0.007	2.314 (0.930-5.762)	0.071
Type IIc morphology	3.164 (1.578-6.341)	0.001	1.017 (0.289-3.583)	0.979
Surface redness	2.616 (1.511-4.528)	< 0.001	0.564 (0.196-1.628)	0.290
Helicobacter pylori status	1.864 (1.087-3.197)	0.024	0.978 (0.433-2.208)	0.958
NBI-modified Kyoto score	9.111 (5.257-15.790)	< 0.001	14.781 (6.621-32.997)1	< 0.001
Conventional Kyoto score	7.438 (4.194-13.191)	< 0.001	N/A2	N/A

¹The narrow-band imaging-modified Kyoto score was analyzed as a categorical variable (≥ 4 vs < 4) in the logistic regression model.

²The conventional Kyoto score was not included in the multivariable model because of overlapping components and conceptual redundancy with the narrow-band imaging-modified Kyoto score.

The reference categories were lesion size < 20 mm, non-IIc morphology, absence of surface redness, past/never Helicobacter pylori infection, and narrow-band imaging-modified Kyoto score < 4, as applicable. OR: Odds ratio; CI: Confidence interval; NBI: Narrow-band imaging; N/A: Not applicable.

Table 4 Predictive performance of the conventional and narrow-band imaging-modified Kyoto scores, % (95% confidence interval)

Parameter	Conventional Kyoto score	NBI-modified Kyoto score	P value
AUC	0.769 (0.707-0.830)	0.862 (0.812-0.911)	0.0021
Optimal cutoff	≥ 4	≥ 4	-
Sensitivity	62.00 (52.00-71.10)	76.10 (67.40-84.80)	-
Specificity	83.50 (77.20-89.80)	83.50 (77.20-89.80)	-
PPV	72.57 (64.70-79.30)	76.47 (69.00-82.70)	-
NPV	75.70 (69.10-81.70)	83.22 (77.50-88.00)	-
Accuracy	74.67 (68.80-80.10)	80.44 (75.26-85.62)	-

¹P value for comparison of the area under the curves using the DeLong test.

The optimal cutoff value was determined using the Youden index. AUC: Area under the receiver operating characteristic curve; NPV: Negative predictive value; PPV: Positive predictive value.

Table 5 Performance of the narrow-band imaging-modified Kyoto score according to Helicobacter pylori infection status, % (95% confidence interval)

Group	n	AUC (95%CI)	Optimal cutoff	Sensitivity	Specificity	PPV	NPV	Accuracy
Current infection	114	0.837 (0.762-0.913)	≥ 4	87.9 (80.3-93.3)	49.7 (41.1-58.3)	54.9 (51.9-58.0)	85.7 (83.0-88.0)	64.0 (58.2-69.5)
Past/never infection	111	0.878 (0.812-0.944)	≥ 4	83.8 (75.0-90.0)	65.5 (57.0-73.2)	62.7 (57.1-68.0)	85.4 (80.1-89.5)	73.2 (67.3-78.4)
P for Delong test1	0.213

¹P value for comparison of the area under the curves between the Helicobacter pylori infection status groups using the DeLong test.

AUC: Area under the receiver operating characteristic curve; CI: Confidence interval; NPV: Negative predictive value; PPV: Positive predictive value.