title: A comparative study of proton-pump inhibitor tests for Chinese reflux patients in relation to the CYP2C19 genotypes.
abstract: BACKGROUND
  The proton-pump inhibitor (PPI) test has been proposed as a valuable tool for diagnosing gastroesophageal reflux disease in Western populations.
  
  
  OBJECTIVE
  We aim to compare the diagnostic accuracy of the PPI test using rabeprazole and pantoprazole in a Chinese population with a higher prevalence of poor PPI metabolization.
  
  
  METHODS
  After diagnostic endoscopy, patients with gastroesophageal reflux disease symptoms were randomly assigned to a 2-week test with rabeprazole (20 mg b.i.d.) or pantoprazole (40 mg b.i.d.). Therapeutic response was assessed with a 5-grade daily record. Genotypes of cytochrome P450 (CYP) 2C19 polymorphism were determined.
  
  
  RESULTS
  Of the 178 patients who completed the study, 92 (51.7%) had erosive esophagitis and 78 (48.3%) were endoscopy-negative reflux disease. On the basis of 50% reduction of symptoms, there was a nonsignificant difference of diagnostic performances between rabeprazole and pantoprazole. For the CYP2C19 genotypes, 138 (87.3%) were determined to be extensive metabolizers (EMs) and 20 (12.7%) were poor metabolizers (PMs). When comparing the EMs and PMs, the diagnostic specificity in the prediction of erosive esophagitis was higher in the EMs (57.6% vs. 20.0%, P=0.040), as was the accuracy (74.6% vs. 50.0%, P=0.023). There were no differences in the sensitivity, positive predictive value, or negative predictive value.
  
  
  CONCLUSIONS
  CYP2C19 genotypic polymorphism was related to a higher possibility of false-positive results for patients who metabolized PPI poorly. High-dose rabeprazole and pantoprazole showed a similar diagnostic performance.
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Ping-Huei
authors.initials: PH
authors.lastname: Tseng
authors.forename: Yi-Chia
authors.initials: YC
authors.lastname: Lee
authors.forename: Han-Mo
authors.initials: HM
authors.lastname: Chiu
authors.forename: Hsiu-Po
authors.initials: HP
authors.lastname: Wang
authors.forename: Jaw-Town
authors.initials: JT
authors.lastname: Lin
authors.forename: Ming-Shiang
authors.initials: MS
authors.lastname: Wu
mesh_terms: D053799:2-Pyridinylmethylsulfinylbenzimidazoles / Q000378:metabolism; D000328:Adult; D000897:Anti-Ulcer Agents / Q000378:metabolism; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics*; D002681:China; D065731:Cytochrome P-450 CYP2C19; D004942:Esophagitis, Peptic / Q000175:diagnosis; D005189:False Positive Reactions; D005260:Female; D005764:Gastroesophageal Reflux / Q000175:diagnosis*; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D000077402:Pantoprazole; D011237:Predictive Value of Tests; D054328:Proton Pump Inhibitors / Q000378:metabolism; D064750:Rabeprazole; D012680:Sensitivity and Specificity
chemical_list: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000897:Anti-Ulcer Agents; D054328:Proton Pump Inhibitors; D064750:Rabeprazole; D000077402:Pantoprazole; D001189:Aryl Hydrocarbon Hydroxylases; C045793:CYP2C19 protein, human; D065731:Cytochrome P-450 CYP2C19