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.