Factors Affecting First-Line Triple Therapy of Helicobacter pylori Including CYP2C19 Genotype and Antibiotic Resistance

Emerging evidence shows that the eradication rate of proton pump inhibitor (PPI)-based triple therapy for the first-line treatment of Helicobacter pylori (H. pylori) has decreased. To clarify the trend of eradication rate of PPI-based triple therapy and to assess the related factors in Korea during the past decade. We prospectively prescribed the triple regimen for seven days (PPI + amoxicillin 1.0 g + clarithromycin 500 mg, twice a day) from March 2003 to May 2013 in 2,202 H. pylori-positive patients. Antibiotic susceptibility tests were performed by the agar dilution method, and the CYP2C19 genotype was determined by the PCR method. In the past decade, the annual eradication rate showed a decreasing trend in intention-to-treat and per-protocol analyses (P = 0.001, both). The antibiotic resistance was increased to amoxicillin (7.2-17.2 %, P = 0.003) and clarithromycin (23.2-37.3 %, P = 0.010) during the study period. The poor metabolizer genotype of CYP2C19 showed a high eradication rate compared to the extensive metabolizer (86.8 vs. 78.2 %, P = 0.035). In addition, age a parts per thousand yen 50 years, female gender, BMI < 25 kg/m(2), amoxicillin and/or clarithromycin resistance were associated with treatment failure on univariate analysis. However, on multivariate analysis, clarithromycin resistance was the only significant factor for treatment failure (OR, 12.76; 95 % CI, 5.58-29.18; P < 0.001). An increase in clarithromycin resistance has led to decreased eradication rate of first-line triple therapy, and; hence, a new strategy is needed to improve the eradication rate of H. pylori.