Background: Our aim was to study the incidence of Helicobacter pylori recurrence in our country and to assess the different variables that might influence it.
Methods: We studied prospectively 331 duodenal ulcer patients (mean age, 48 +/- 14 years, 71% male) in whom H. pylori had been eradicated. Several therapies were used, classified as low-efficacy (omeprazole + amoxycillin, 32% eradication rate; omeprazole + amoxycillin + metronidazole, 56%) and high-efficacy therapies (omeprazole + clarithromycin + amoxycillin or metronidazole, 88%; bismuth triple therapy, 77%). One month after completion of therapy an endoscopy with biopsies and/or 13C-urea breath test was performed. A breath test was carried out again at 6 months, 1 year, and 2 years, to study H. pylori recurrences. Endoscopy (with biopsies) was performed only to confirm recurrences. Multiple logistic regression analysis was used. Differences between Kaplan-Meier curves were evaluated with the log-rank test.
Results: Sixty-seven patients were followed up for 6 months, 136 for 1 year, and 128 for 2 years, giving 425 patient-years of follow-up. A total of 18 H. pylori recurrences was observed (12 at 6 months, 4 at 1 year, and 2 after 2 years), yielding a yearly recurrence of 4.2% patient-years(-1). The respective risk of H. pylori recurrence for each period was 3.6% (95% confidence interval (CI), 2.1%-6.2%), 1.5% (0.6%-3.8%), and 1.5% (0.4%-5.5%). The probability of being H. pylori-negative at 6 months, 1 year, and 2 years was, respectively, 96.4% (94.4%-98.4%), 94.9% (92.5%-97.4%), and 93.4% (90.3%-96.6%). Duodenal ulcer was found in half of the reinfected patients. The recurrence rate at 6 months was 10.3% (5.7%-18%) in patients <40 years old and only 0.85% (0.2%-3.1%) in those > or =40 years old (P = 0.0002). Of the patients who became reinfected at 6 months 27% (6%-61%) had delta breath test values between 3 per thousand and 5 per thousand 1 month after therapy, whereas only 4.6% (2.7%-7.7%) of non-reinfected patients had delta after eradication > or =3 per thousand (P = 0.0097). H. pylori recurrence at 6 months was 8.2% (4.5%-15%) in patients previously treated with low-efficacy therapies and only 1.7% (0.7%-4.3%) when high efficacy therapies were used (P = 0.0098). In the multivariate analysis age (odds ratio (OR), 0.9; 95% CI, 0.8-0.96; P = 0.0008), the delta breath test value after therapy (OR, 2.2; CI, 1.2-4.1; P = 0.0076), and therapy regimen (OR, 6.4; CI, 1.5-27; P = 0.0109) were the only variables that correlated with H. pylori recurrence at 6 months. Differences were observed when Kaplan-Meier curves were compared, depending on age (<40 or > or =40 years; P = 0.0054), breath test value (delta) 1 month after therapy (<3 or > or =3 per thousand; P = 0.0089), and therapy regimen (high or low efficacy; P = 0.0006).
Conclusions: Risk of post-eradication H. pylori recurrence is higher during the first 6 months, which suggests that most recurrences during this period are recrudescences and not true reinfections. Patients who have H. pylori recurrence tend to be younger and have higher delta 13C-urea breath test values after therapy, which suggests that a 'negative' value between 3 per thousand and 5 per thousand needs to be confirmed. Recurrence of H. pylori is more frequent in patients treated with low-efficacy therapies but is exceptional when high-efficacy therapies are used, in which case post-therapy eradication can be safely confirmed at 4 weeks. Finally, recurrence of H. pylori is clinically relevant, as ulcer recurrence is observed in a considerable proportion of these patients.