Independent risk factors predicting eradication failure of standard bismuth quadruple therapy for the first-line treatment of Helicobacter pylori infection in Taiwan

Bismuth quadruple therapy is recommended as the choice treatment for Helicobacter pylori (H. pylori) infection in areas of either low or high clarithromycin resistance in the Maastricht VI/Florence Consensus Report. However, the optimal treatment duration and drug dosages of bismuth quadruple therapy remain unclear. The study aimed to search the independent risk factors predicting eradication failure of standard bismuth quadruple therapy in the first-line treatment of H. pylori infection. From July 2014 to June 2022, 274 H. pylori-infected patients who received 10-day or 14-day bismuth quadruple therapy containing a proton pump inhibitor, bismuth, tetracycline and metronidazole were included for the study. Post-treatment H. pylori status was assessed at least 4 weeks after completion of treatment. The relationships between eradication rate and 13 clinical parameters were analyzed by univariate and multivariate analyses. The eradication rates of standard bismuth quadruple therapy were 93.8% and 94.2% by intention-to-treat and per-protocol analyses, respectively. Univariate analysis revealed that patients harboring metronidazole-resistant strains had a lower eradication rate than those harboring metronidazole-susceptible strains (88.7% [55/62] vs. 96.7% [148/153]). The other factors including smoking, treatment duration and drug adherence were not significantly associated with cure rate. Multivariate analysis revealed that metronidazole resistance of H. pylori was the only independent risk factors related to eradication failure of standard bismuth quadruple therapy with an odds ratio of 3.8 (95% CI: 1.2-12.4). In conclusion, metronidazole resistance is an independent risk factor predicting eradication failure of standard bismuth quadruple therapy in the first-line treatment of H. pylori infection. There is no difference in eradication efficacy between 10-day and 14-day bismuth quadruple therapies in Taiwan.