Clarithromycin resistance and female gender affect Helicobacter pylori eradication failure in chronic gastritis

Background/Aims: The eradication rate of the first-line triple therapy (a proton pump inhibitor, clarithromycin, and amoxicillin) for Helicobacter pylori infection has gradually decreased in Korea. We evaluated whether clinical parameters, clarithromycin resistance, and CYP2C19 genotype can affect the eradication failure. Methods: A total of 203 patients with H. pylori-positive chronic gastritis were consecutively enrolled. They received clarithromycin-based triple therapy for 7 days. A clarithromycin resistance test was performed by detection of A2142G and A2143G point mutations in H. pylori 23S rRNA. The CYP2C19 genotype was examined for polymorphism G681A of exon 5 and G636A of exon 4 by polymerase chain reaction with restriction fragment length polymorphism. Eradication was assessed by a ¹³C-urea breath test 4 weeks after treatment. Results: Of 203 patients, 190 completed the study. The eradication rate was 64.0% according to intention-to-treat analysis and 68.4% by per-protocol analysis. CYP2C19 genotypes were identified as follows: 75 poor metabolizers, 75 intermediate metabolizers, and 40 rapid metabolizers. Nonetheless, this polymorphism was not significantly associated with eradication failure (p = 0.682). Clarithromycin resistance was detected in 33/190 patients (17.4%), and their eradication rate was zero. Clarithromycin resistance (odds ratio [OR], 19.13; 95% confidence interval [CI], 9.35 to 35.09) and female gender (OR, 1.73; 95% CI, 1.15 to 4.25) were significantly associated with eradication failure. The other clinical parameters such as age, cigarette smoking, alcohol intake, the body mass index, hypertension, and diabetes were not significantly associated with eradication. Conclusions: Clarithromycin resistance and female gender are factors affecting H. pylori eradication failure in patients with chronic gastritis.