Recurrence of Helicobacter pylori infection after eradication: incidence and variables influencing it.

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.