Gastric juice ammonia and urea concentrations and their relation to gastric mucosa injury in patients maintained on chronic hemodialysis.

Purpose: This study was undertaken to test the hypothesis that high concentrations of urea in gastric juice would have an influence on Helicobacter pylori infection in patients maintained on chronic hemodialysis (HD).

Material and methods: We investigated 30 patients (17 males, 13 females; mean age 50.8 +/- 2.9 years) with end-stage renal disease (ESRD) undergoing hemodialysis treatment (HD) for at least 6 months, who were compared to 31 patients (16 males, 15 females; mean age 61.3 +/- 2.2 years) with dyspeptic symptoms. Biopsies from the gastric antrum and body were taken for histological investigation. Urea and ammonia were measured in gastric juice, and the severity of gastritis was evaluated according to Sydney criteria.

Results: H. pylori infection was found in 19 (63%) HD patients and in 22 (71%) control subjects. Gastric juice urea concentration was significantly higher in HD patients than in controls and H. pylori infection caused a significant decrease in urea concentration in both groups. There was an inverse correlation between urea and ammonia concentration in gastric juice in both groups. Ammonia concentration in both groups was higher in H. pylori infected patients. In H. pylori negative subjects ammonia/urea ratio was lower in HD patients in comparison to controls. Ammonia/urea ratio was raised by H. pylori infection in both groups, and the difference between HD and control groups persisted. H. pylori infection was associated with polymorphonuclear infiltration of gastric mucosa. There was a significant correlation between gastric ammonia and mucosal polymorphonuclear leukocytes infiltration and gastritis score.

Conclusions: Higher urea levels in the gastric juice of chronically hemodialyzed patients do not seem to be a risk factor for infection with Helicobacter pylori.