Association between CYP2C19 extensive metabolizer phenotype and childhood anti-reflux surgery following failed proton pump inhibitor medication treatment

When pediatric gastroesophageal reflux disease (GERD) that is refractory to proton pump inhibitor (PPI) medication treatment is identified in clinical practice and anti-reflux surgery (ARS) is being considered, genetic factors related to PPI metabolism by the CYP2C19 enzyme are currently not part of the clinical decision-making process. Our objective was to test the hypothesis that the distribution of the extensive metabolizer (EM) phenotypes among children undergoing ARS after failing PPI therapy would differ compared to controls (children with no history of ARS). We conducted a case-control study between children across the Nemours Health System from 2000 to 2014 who received ARS after failing PPI therapy and a control group comprised of healthy children. Our results demonstrated 2.9% of ARSs vs 20.8% of controls were poor metabolizers (PMs), 55.9% of ARSs vs 49.0% of controls were normal metabolizers (NMs), and 41.2% of ARSs vs 30.2% of controls were EMs; p = 0.035. Next, we performed a multiple-regression model to account for race as a potential confounding variable and the EM group was significantly associated with ARS compared to controls (OR 9.78, CI 1.25–76.55, p < 0.03).

Conclusion: Among children with medically refractory GERD despite PPI therapy, carriage of CYP2C19*17 allele corresponding to the EM phenotype was associated with ARS. Prospective comparative personalized medicine effectiveness studies are needed to determine if CYP2C19 genotype-guided dosing improves response to PPI therapy without a corresponding increase in adverse effects in children.