Endoscopic Kyoto classification of Helicobacter pylori infection and gastric cancer risk diagnosis

Table 1 Kyoto classification score

Kyoto classification	Score
Atrophy
None, C1	0
C2 and C3	1
O1-O3	2
Intestinal metaplasia
None	0
Antrum	1
Corpus and antrum	2
Enlarged folds
Absence	0
Presence	1
Nodularity
Absence	0
Presence	1
Diffuse redness
None	0
Mild (with RAC)	1
Severe	2
Kyoto score	0-8

RAC: Regular arrangement of collecting venules.

Table 2 Diagnostic value of Kyoto classification for Helicobacter pylori infection

Endoscopic findings	Ref.	Year	No. of subjects	Sensitivity	Specificity	PPV	NPV
Diagnosis for current H. pylori infection
Enlarged folds	Kato et al[59]	2013	275	58.5	79.5	76.9	62.2
Enlarged folds	Mao et al[60]	2016	256	60.2	92.3	86.0	74.6
Enlarged folds	Yoshii et al[61]	2019	498	23.1	96.6	56.2	87.0
Nodularity	Laine et al[57]	1995	52	32.1	95.8	90.0	54.8
Nodularity	Kato et al[59]	2013	275	5.3	98.8	75.0	59.4
Nodularity	Yoshii et al[61]	2019	498	6.4	98.3	41.7	84.9
Diffuse redness	Kato et al[59]	2013	275	83.4	66.9	73.8	78.4
Diffuse redness	Mao et al[60]	2016	256	57.5	95.8	91.5	74.7
Diffuse redness	Yoshii et al[61]	2019	498	60.0	94.7	65.6	93.3
Diagnosis for negative H. pylori infection
RAC	Yagi et al[58]	2002	557	91.1	97.9	95.0	96.2
RAC	Kato et al[59]	2013	275	93.6	48.0	87.0	66.8
RAC	Mao et al[60]	2016	256	86.7	90.2	87.5	89.6
RAC	Garcés-Durán et al[62]	2019	140	100.0	49.0	47.3	100.0

PPV: Positive predictive value; NPV: Negative predictive value; RAC: Regular arrangement of collecting venules; H. pylori: Helicobacter pylori.

Table 3 Gastric cancer incidence according to endoscopic atrophy

Ref.	Population	No. of subjects	No. of cancers	Duration, yr	Gastric cancer incidence, %/yr
					Mild	Moderate	Severe
Take et al[70], 2011	Post eradication with peptic ulcer	1674	28	5.6	0.04	0.28	0.62
Shichijo et al[71], 2016	Post eradication	573	21	6.2	0.071	0.341	1.601
Kaji et al[72], 2019	Medical examination	12941	63	3.7	0.10	0.16	0.31
	Post eradication	2571	20	3.7	0.06	0.12	0.42

¹Incidence was calculated by dividing the incidence per 10 years by 10.

Table 4 Odds ratios of endoscopic findings for gastric cancer

Endoscopic findings	Ref.	Population	No. of subjects	Odds ratio
Atrophy	Masuyama et al[76], 2015	Without eradication	27777	14.21
Atrophy	Sekikawa et al[77], 2016	Screening	1823	7.21
Intestinal metaplasia	Sugimoto et al[74], 2017	Endoscopic gastritis	1200	5.0
Enlarged folds	Nishibayashi et al[73], 2003	H. pylori positive	276	5.0
Nodularity	Nishikawa et al[49], 2018	H. pylori positive	674	13.9
RAC	Majima et al[75], 2019	Post eradication	194	0.4

¹Odds ratio for open-type atrophy calculated with closed-type atrophy as a reference. RAC: Regular arrangement of collecting venules; H. pylori: Helicobacter pylori.