Background: The ¹³C-urea breath test is the best non-invasive test to validate Helicobacter pylori eradication. Serology is unreliable for this purpose due to the slow and unpredictable decline in the antibodies titer.

Objectives: To characterize a specific group of patients who were treated for H. pylori and tested for successful eradication by ¹³C-UBT[1] in our central laboratory and to correlate the eradication success rate with specific drug combinations, and to evaluate other factors that may influence eradication success.

Methods: ¹³C-UBT for H. pylori was performed in the central laboratory of Clalit Health Services. The breath test was performed by dedicated nurses in 25 regional laboratories and the samples were analyzed by a mass spectrometer (Analytical Precision 2003, UK). The physician who ordered the test completed a questionnaire computing demographic data (age, gender, origin), indication, use of non-steroidal anti-inflammatory drugs or proton pump inhibitor, and combination of eradication therapy.

Results: Of the 1,986 patients tested to validate successful H. pylori eradication, 539 (27%) had a positive test (treatment failure group) and 1,447 (73%) had a negative test (successful treatment group). Male gender, older age and European-American origin predicted better eradication rates. Dyspeptic symptoms and chronic PPI[2] therapy predicted treatment failure. Combination therapy that included clarithromycin had a higher eradication rate than a combination containing metronidazole. The combination of omeprazole, amoxicillin and clarithromycin achieved an eradication rate of 81.3%, which was better than the combination of omeprazole, metronidazole and clarithromycin (77.2%) (not significant), or of omeprazole, amoxicillin and metronidazole (66.1%) (P < 0.01).

Conclusion: Gender, age, origin, dyspepsia and PPI therapy may predict H. pylori eradication results. Our findings also support an increase in metronidazole resistance of H. pylori strains in Israel, as described in other countries. We recommend combination therapy with omeprazole, amoxicillin and clarithromycin and avoidance of metronidazole as one of the first-line eradication drugs.