Evaluation of the Usefulness and Convenience of the Kyoto Classification of Gastritis in the Endoscopic Diagnosis of the Helicobacter pylori Infection Status

Background/Aims: The Kyoto Classification of Gastritis was published in 2014. Although this classification is now widely used in Japan, its usefulness and convenience have not been sufficiently evaluated. This study aimed to evaluate the usefulness and convenience of this classification in the endoscopic diagnosis of Helicobacter pylori infection. Methods: We made a test for the endoscopic diagnosis of H. pylori infection comprising 30 cases who had representative endoscopic features of non-, active, or inactive gastritis. Thirty-eight participants took the test before and after a brief mini-lecture on the Kyoto Classification of Gastritis. Eighteen participants took the test again 3 months later. We investigated the accuracy before, just after, and 3 months after the mini-lecture. Results: The accuracy of endoscopists after the lecture was significantly improved in comparison to before the lecture (77.6 vs. 83.3%). Medical students also showed significantly improved accuracy after the lecture (56.7 vs. 71.7%). Among endoscopists, this improvement was maintained after 3 months. Before the lecture, the accuracy of diagnosing non-gastritis was 90.3%; it tended to be further improved 3 months later (96.5%). A >10% point increase was observed in diagnosing active (72.7-83.3%) and inactive gastritis (73.2-84.3%) at 3 months after the lecture in comparison to before the lecture. Conclusion: A brief mini-lecture on the Kyoto Classification of Gastritis improved the accuracy in the endoscopic diagnosis of gastritis, indicating that understanding this classification is useful for the prompt diagnosis of H. pylori infection during esophagogastroduodenoscopy.