Second-Line Bismuth-Containing Quadruple Therapy for Helicobacter pylori Infection: A 12-Year Study of Annual Eradication Rates

Background: Bismuth-containing quadruple therapy (BQT) consisting of a proton-pump inhibitor (PPI), bismuth, metronidazole and tetracycline is recommended as a second-line treatment for Helicobacter pylori (H. pylori) infection when PPI-based standard triple therapy (STT) consisting of a PPI, amoxicillin and clarithromycin is unsuccessful. The purpose of this study was to analyze the long-term results of BQT as a second-line therapy to determine its effectiveness. Methods: This study included 643 subjects who failed first-line STT and received 7 or 10–14 days of BQT as a second-line therapy. We retrospectively analyzed the annual H. pylori eradication rates, demographic factors and adverse events. Results: The overall eradication rates by intention-to-treat (ITT) and per-protocol (PP) analyses were 80.7% (519/643) and 93.3% (519/556), respectively. By PP analysis, the eradication rates for 2008–2011, 2012–2015, and 2016–2019 were 93.3%, 91.0%, and 96.4%, respectively (p = 0.145). There were no significant differences between the 7-day group and the 10–14-day group in both the ITT (79.7% vs. 86.0%, p = 0.148) and the PP analyses (92.7% vs. 96.6%, p = 0.187). A multivariate analysis showed that current smoking was associated with eradication failure. Eighty-nine subjects (16.0%) suffered adverse events, mainly gastrointestinal symptoms, but only six cases were severe. Conclusions: BQT as a second-line therapy is an effective treatment for H. pylori. Treatment for 10–14 days showed a higher eradication rate compared with a 7-day regimen, but not significantly.