Low Re-infection Rate of Helicobacter pylori after Successful Eradication in Thailand: A 2 Years Study.

Background: H. pylori is an important cause of chronic gastritis, peptic ulcers and gastric cancer. Re-infection rates after successful eradication vary in different regions of the world but only limited studies have been performed in ASEAN Countries to clarify this important issue. The present study was designed to evaluate the H. pylori re-infection rate and predictors of re-infection in Thailand. Methods: We recruited patients with chronic gastritis after 1 and 2 years successful H. pylori eradication from Thammasat University Hospital, Pathumthani (Central urban area) and Maesod district, Tak (Northern rural area), Thailand. 13C-UBT was performed to evaluate re-infection status after cessation of PPI, H2 blocker and antibiotics for at least 4 weeks. Statistical analysis was performed using SPSS for Windows Version 22.0 (IBM Corp., Armonk, NY). Results: A total of 105 subjects were enrolled (40 M and 65F with a mean age of 53.1 years). The overall re-infection rate was 6/105 (5.7%). The 1-year and 2-year H. pylori re-infection rates after successful eradication were only 5.1% (2/39) and 6.1% (4/66). 1-year and 2-year reinfection rates in urban areas were 2/39 (5.1%) and 1/26 (3.8%), while the 2-year reinfection rate in rural areas was 3/40 (7.5%). Location (urban vs rural area) and sex did not show any association with either 1-year or 2-year H. pylori re-infection. With 2-year reinfection, the mean age of H. pylori re-infected patients was significantly higher than those who remained cured (63.0 years vs. 51.6 years, p-value = 0.01). The annual H. pylori infection rate was 2.9%. Conclusions: 1-year and 2-year H. pylori re-infection rates after successful eradication in Thailand appear low in both rural and urban areas. H. pylori eradication for prevention of significant upper GI disease should be recommended and confirmation of successful eradication should be the aim. Patients at higher risk such as the elderly should be monitored for possible risk of H. pylori re-infection.