Relation between gastric acid output, Helicobacter pylori, and gastric metaplasia in the duodenal bulb

Abstract

Background - Factors that determine gastric metaplasia in the duodenal bulb are ill defined. It is more common and extensive in the presence of high acid output and possibly in the presence of Helicobacter pylori. However, no quantitative relation between acid output and the extent of gastric metaplasia has been demonstrated and its relation to H pylori is uncertain. Aim - To determine the relation between H pylori infection and acid output and the presence and extent of gastric metaplasia in the duodenal bulb. Subjects - H pylori positive and negative patients with duodenal ulcer and healthy controls were studied. Methods - Quadrantic duodenal bulb biopsy specimens were taken and the presence and extent of gastric metaplasia determined using a computer enhanced image intensifier. Basal and stimulated acid outputs were measured. Results - Gastric metaplasia was significantly (p < 0.05) more common and significantly (p < 0.05) greater in extent in patients with duodenal ulcer than in controls. Neither the prevalence or extent of gastric metaplasia was affected by H pylori status. There were significant (p < 0.01) direct correlations between acid output and extent of gastric metaplasia. Conclusions - Prevalence and extent of gastric metaplasia are not related to H pylori in controls, or in patients with duodenal ulcer. Rather, high acid response to gastrin may be more important.