Twice‐daily intake of bismuth‐based quadruple therapy for first‐line Helicobacter pylori eradication: A retrospective study on 10‐day, 14‐day, and half‐dose antibiotic therapy

Abstract Background/Aims In areas with >15% clarithromycin resistance, bismuth‐based quadruple therapy is recommended for first‐line Helicobacter pylori eradication. This study aimed to determine the efficacy of the twice‐daily intake of bismuth‐based quadruple therapy among 10‐day, 14‐day, and half‐dose antibiotic regimens. Methods From May 2021 to March 2023, H. pylori ‐infected Korean adults were administered tetracycline (1 g), metronidazole (750 mg), bismuth potassium citrate (300 mg), and lansoprazole (30 mg) twice daily, after breakfast and dinner, for 10 days. The regimen was administered for 14 days if the body weight was ≥70 kg or if the patient had reinfection. Half doses of antibiotics were administered for 14 days if there was a risk of drug interactions or if the patient was aged ≥75 years. The 13 C‐urea breath test was performed after 6 weeks. Results Among the 1258 infected Koreans, 85.1% (412/484) in the 10‐day, 84.3% (498/591) in the 14‐day, and 86.3% (158/183) in the half‐dose antibiotic groups followed the instructions. In the per‐protocol (PP) analysis, eradication rates were higher in the 10‐day (90.5%, p = 0.019) and 14‐day (90.2%, p = 0.023) groups than in the half‐dose group (83.5%). In the intention‐to‐treat (ITT) analysis, eradication rates were higher in the 10‐day group (80.6%) than in the half‐dose group (73.2%, p = 0.039). In the half‐dose group, the eradication rate was lower in patients aged ≥75 years (PP: 74.6%, ITT: 66.2%) than in those with a risk of drug interactions (PP: 89.7% [ p = 0.017], ITT: 82.4% [ p = 0.019]). Conclusions Twice‐daily intake of bismuth‐based quadruple therapy for 10–14 days showed an eradication rate of >90% in the PP analysis. A 10‐day regimen could be administered to eradication‐naive patients with a body weight below 70 kg. A half‐dose antibiotic regimen might be recommended to patients with a risk of drug interactions but not to those aged ≥75 years simply due to old age.