Diagnosis of histological gastritis based on the Kyoto classification of gastritis in Japanese subjects – including evaluation of aging and sex difference of histological gastritis

Objectives The Kyoto classification of gastritis was established for diagnosing Helicobacter pylori (H. pylori) infection via endoscopic findings. We investigated the role of the Kyoto classification of gastritis in the diagnosis of H. pylori infection and histological gastritis in Japanese individuals. Moreover, the histological findings of gastritis in H. pylori infection were examined based on age and sex differences. Methods We selected 561 patients aged 20-79 years who underwent gastroduodenal endoscopy at our hospital between 2010 and 2018. Endoscopic biopsy specimens from the antrum and corpus were used to investigate H. pylori infection and histology. Endoscopic findings were based on the Kyoto classification of gastritis, and histological findings were based on the updated Sydney System. Results Endoscopic findings based on the Kyoto classification of gastritis (H. pylori positive, 303 patients; H. pylori negative, 258 patients, based on endoscopic findings) had 98.7% sensitivity and 98.4% specificity for histological gastritis. In addition, endoscopic findings in the three age groups (20-39, 40-59, and 60-79 years) had high sensitivity and specificity. Atrophy and intestinal metaplasia were found only in the H. pylori-positive group and progressed with age. Histological inflammation of pyloric mucosa in the younger age group of H. pylori-positive patients was significantly higher than that in the elderly group. Significant inflammation was observed in young women. Conclusions The Kyoto classification of gastritis can not only diagnose H. pylori infection but also detect histological gastritis. Histological gastritis has varying characteristics of inflammation, atrophy, and intestinal metaplasia, depending on age and sex.