Cytotoxin-associated gene A-positive Helicobacter pylori infection in the elderly. Association with gastric atrophy and intestinal metaplasia.

To evaluate if the infection with strains of cytotoxin-associated gene A (CagA)-positive Helicobacter pylori is associated with either peptic ulcer and gastric atrophy or intestinal metaplasia in the elderly, we studied 71 H. pylori-positive patients older than 62 years old (34 men, 37 women; mean age, 77.5 years; range, 62-89 years) affected with gastric ulcer (GU) (n = 10), duodenal ulcer (DU) n = 22), or chronic gastritis (CG) (n = 39). H. pylori infection was documented by means of gastric histology, rapid urease test, and polymerase chain reaction (PCR) assay performed on gastric biopsies using two sets of primers: one for the ureC gene specific for H. pylori, and the second specific for the CagA gene. H. pylori-CagA positivity was significantly more common in patients with GU (9 of 10, 90%) than with DU (11 of 22, 50%; p < 0.05) or CG (17 of 39, 43.5%; p = 0.01). Gastric atrophy and intestinal metaplasia were significantly more common in CagA-positive patients than in CagA-negative patients (gastric atrophy: 40.54% vs 11.76, p = 0.007; intestinal metaplasia: 40.54% vs 14.70%, p = 0.01). No difference in prevalence of gastric atrophy and intestinal metaplasia was found in patients divided according to pathology (GU, DU, or CG). Logistic regression demonstrated that gastric atrophy and intestinal metaplasia were independent factors significantly associated with CagA-positivity (gastric atrophy: odds ratio = 4.53, 95% confidence interval 1.25-16.4; intestinal metaplasia: odds ratio = 3.44, 95% confidence interval 1.01-11.7). Our findings help to confirm the hypothesis that an infection with CagA-positive H. pylori strains may be catalytic in inducing gastric changes which can evolve into malignancies.