Abstract
BACKGROUND: The extent of disease severity remains unclear among CYP2C19 rapid and ultra-rapid metabolizers with refractory symptoms of gastroesophageal reflux disease (GERD) on chronic proton-pump inhibitors (PPIs). AIMS: To determine the impact of CYP2C19 metabolizer status in relation to chronic PPI therapy with a focus on the extent of esophageal inflammation, acid exposure, and motor function. METHODS: This retrospective study included 54 patients with refractory GERD symptoms who underwent CYP2C19 genotyping for PPI metabolism, esophagogastroduodenoscopy, ambulatory pH study, and high-resolution esophageal manometry. Patients were divided into three groups: normal metabolizer (NM) group, intermediate metabolizer/poor metabolizer (IM/PM) group, and rapid metabolizer/ultra-rapid metabolizer (RM/UM) group. The Chi-square test was used to analyze categorical variables, and one-way ANOVA for comparing means. RESULTS: Rapid metabolizer/ultra-rapid metabolizer (RM/UM) group more frequently had either Los Angeles grade C or D GERD (7/19, 36.8% vs 1/21, 4.8%, P = 0.011) and metaplasia of the esophagus (9/19, 47.4% vs 2/21, 9.5%, P = 0.007) when compared to the NM group. RM/UM group were more frequently offered dilatation for nonobstructive dysphagia (8/19, 42.1% vs 3/21, 14.3%, P = 0.049) and more exhibited a hypotensive lower esophageal sphincter (LES) resting pressure compared to the NM group (10/19, 52.6% vs 4/21, 19%, P = 0.026). All three groups exhibited comparable DeMeester scores when PPIs were discontinued 72 hours before the ambulatory pH study. CONCLUSION: CYP2C19 RMs and UMs on chronic PPI with refractory GERD symptoms exhibited greater esophageal mucosal inflammation, as observed both endoscopically and histologically, and more were found to have hypotensive LES resting pressures and more were offered esophageal dilatation.