title: Dual Ambulatory pH Monitoring in Patients with Gastroesophageal Reflux Rendered Asymptomatic with Proton Pump Inhibitor Therapy.
abstract: BACKGROUND
  Studies have suggested that proton pump inhibitor (PPI) therapy in gastroesophageal reflux disease (GERD) achieves high rates of esophageal acid normalization.
  
  
  OBJECTIVE
  Our aims were to investigate the adequacy of esophageal and gastric acid suppression in reflux patients rendered asymptomatic on optimized PPI therapy.
  
  
  METHODS
  We retrospectively analyzed outcomes of dual-sensor, ambulatory 24-h pH monitoring in referred persistent reflux patients rendered asymptomatic on PPI therapy. After optimization, we analyzed esophageal and gastric pH profiles to assess acid suppression and examine differences between PPIs. In patients with repeat studies, comparisons between different PPI doses were made.
  
  
  RESULTS
  Of 172 asymptomatic GERD patients, 75 (43.6 %) achieved symptomatic remission with once-daily dosing PPI, and 97 (56.4 %) patients required twice-daily dosing. Of the entire cohort, 93 (54.1 %) had abnormal and 79 (45.9 %) had normal esophageal pH profiles, with mean percent time pH < 4.0 of 14.3 and 2.4, respectively (p < 0.0001). The percent time esophageal pH was abnormal did not correlate with the percent time gastric pH was abnormal (p = 0.17). Different PPI formulations demonstrated differences in gastric--not esophageal--pH times, with esomeprazole exhibiting superior gastric pH suppression (p < 0.0001). Overall, gastric pH control remained suboptimal, with pH < 4.0 ranging between 30 and 50 %. Among patients with sequential pH studies, those with higher PPI dose had improved esophageal pH profiles (p < 0.01).
  
  
  CONCLUSIONS
  In GERD patients rendered asymptomatic on PPI therapy, most continue to experience abnormal esophageal and gastric acid exposure. The efficacy of acid suppression therapy, in certain patients, may be much lower than previously thought.
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, 300 Pasteur Drive, M-211, Stanford, CA, 94306, USA.
authors.forename: David
authors.initials: D
authors.lastname: Lin
authors.forename: George
authors.initials: G
authors.lastname: Triadafilopoulos
mesh_terms: D050782:Esophageal pH Monitoring; D004947:Esophagus / Q000187:drug effects / Q000378:metabolism; D005260:Female; D005744:Gastric Acid / Q000378:metabolism; D005745:Gastric Acidity Determination; D005753:Gastric Mucosa / Q000187:drug effects / Q000378:metabolism; D005764:Gastroesophageal Reflux / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D054328:Proton Pump Inhibitors / Q000627:therapeutic use*; D012074:Remission Induction; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D054328:Proton Pump Inhibitors