24-hour gastric pH and extent of duodenal gastric metaplasia in Helicobacter pylori-positive patients.

BACKGROUND & AIMS: Gastric metaplasia (GM) is essential to explain duodenal colonization by Helicobacter pylori. It seems to be acid induced but also occurs in H. pylori-positive patients with nonulcer dyspepsia (NUD), who are not acid hypersecretors. The aim of this study was to assess the circadian gastric acidity of 47 patients with duodenal ulcers (DUs) and 32 patients with NUD, both H. pylori positive, and its correlation to duodenal GM extent. METHODS: H. pylori was detected by histology and CLOtest, and GM was diagnosed and graded on four bulb biopsy specimens. Each patient underwent 24-hour gastric pH-metry, and the relation between gastric pH and GM extent was assessed by factorial analysis. RESULTS: Gastric pH was greater in patients with NUD than in patients with DU during 24 hours, night and daytime (P < 0.03-0.005). Gastric pH differed significantly (P < 0.0002) in relation to GM extent between the two populations, whereas no difference was found among the pH values of GM degrees. A significant increase in 24-hour gastric pH was associated with greater GM in patients with DU, whereas the opposite occurred in patients with NUD (P < 0.007). CONCLUSIONS: The lower gastric acidity in patients with NUD than in patients with DU and the lack of correlation between gastric pH and the various GM degrees in the two H. pylori-positive populations suggest that gastric hyperacidity is not associated with duodenal GM.