Chuan-Guo Guo1, Fang Jiang1, Ka Shing Cheung1, Bofei Li2, Poh Hwa Ooi1, Wai K Leung1

1Department of Medicine, University of Hong Kong, Hong Kong, China, 2Department of Surgery, University of Hong Kong, Hong Kong, China

Background/Aims: The success rate of clarithromycin-containing triple therapy for Helicobacter pylori (HP) is declining, particularly in regions with high background antibiotic resistance. We aimed to determine the trend and risk factors associated with failure of clarithromycin-containing triple therapy in Hong Kong over the past 15 years.

Methods: This is population-based retrospective cohort study involving all adult HP infected patients who had received the first course of clarithromycin-containing triple therapy in 2003-2018. Failure of eradication was identified by the need of retreatment. Logistic regression model was used to evaluate the risk of retreatment conditioned by the year of treatment and adjusted for age, sex, duration of therapy and triple therapy type.

Results: 120,633 HP infected patients were included with an overall retreatment rate of 9.99%, which slowly increased from 9.59% in 2003 to 11.3% in 2016 (P for linear trend: 0.049). Men had a lower retreatment rate than women (8.86% vs 11.0%; OR 0.83, 95% CI 0.80-0.86). Notably, younger patients (18-44 years) had the highest retreatment rate of 11.6%, which progressively reduced in older groups (45-59 years: 10.5%, OR 0.89, 95% CI 0.85-0.93; 60-74 years: 9.20%, OR 0.80, 95% CI 0.76-0.84; 75 years or older: 7.12%, OR 0.61, 95% CI 0.57-0.66). Triple therapy containing metronidazole had a significantly higher retreatment rate than amoxicillin (18.9% vs 9.65%, OR 2.11, 95% CI 1.96-2.26). Though 7-day therapy was most frequently used (89.8%), longer treatment duration was associated with lower retreatment rate (10 days: OR 0.80, 95% CI 0.73-0.87; 14 days: OR 0.76, 95% CI 0.68-0.84 vs 7 days).

Conclusion: Failure rates of clarithromycin-containing triple therapy slowly increased in Hong Kong over the past 15 years. Triple therapy containing amoxicillin for >7 days were associated with lower retreatment rate. Younger patients were unexpectedly found to have the highest treatment failure rate, which deserved further attention.

Keywords: Helicobacter pylori, treatment, time trend