The long-term impact of Helicobacter pylori eradication on gastric histology:: A systematic review and meta-analysis

Background: Helicobacter pylori infection is a crucial factor in the multistep carcinogenic process of gastric cancer. In this process the gastric mucosa evolves through the stages of acute gastritis, chronic gastritis, gastric atrophy (GA), and intestinal metaplasia (IM) before developing gastric adenocarcinoma. Aims: The main aim of this study was to systematically review the long-term effects of H. pylori eradication on gastric histology (i.e. effects on GA and IM for both antrum and corpus) by meta-analyzing all relevant studies. Methods: Extensive English-language medical literature searches for human studies were performed through October 2006, using suitable key words. Pooled estimates [odds ratio (OR) with 95% confidence intervals (CI)] were obtained using random-effects model. Results: For antrum GA the pooled OR with 95% CI was 0.554 (0.372-0.825), p = 0.004. For corpus GA the pooled OR was 0.209 (0.081-0.538), p < 0.001. For antrum IM the pooled OR was 0.795 (0.587-1.078), p = 0.14. For corpus IM the pooled OR was 0.891 (0.663-1.253), p = 0.506. Conclusion: The results showed significant improvement of GA, whereas improvement was not shown for IM.