title: An evaluation of the clinical implications of acid breakthrough in patients on proton pump inhibitor therapy.
abstract: BACKGROUND
  Some patients with gastro-oesophageal reflux disease continue to experience symptoms despite therapy with proton pump inhibitors. One recently proposed cause is the occurrence of nocturnal acid breakthrough.
  
  
  OBJECTIVE
  : To investigate the relationship between acid breakthrough occurrence (nocturnal and daytime) and refractory symptoms among patients with gastro-oesophageal reflux disease on proton pump inhibitors.
  
  
  METHODS
  Fifty-two consecutive patients with persistent symptoms of gastro-oesophageal reflux disease despite proton pump inhibitor therapy underwent 24-h pH study at the Mayo Clinic between January 1 and November 10, 1999. Relevant data were extracted and analysed.
  
  
  RESULTS
  Fifty-two patients, 18 males and 34 females, were eligible for the study. The mean age was 53 +/- 2.2 years. Thirty-seven patients (71%) had nocturnal acid breakthrough, and 36 (69%) had daytime acid breakthrough. Sixty per cent of patients experienced both nocturnal and daytime acid breakthrough, whereas 19% had neither. Among those with nocturnal and daytime acid breakthrough, only 36% and 33% of symptoms, respectively, were associated with gastro-oesophageal reflux episodes. The proportion of patients with symptoms and the mean symptom scores were not significantly different between those with and without acid breakthrough.
  
  
  CONCLUSIONS
  Gastric acid breakthrough occurs nocturnally and during the daytime in patients on proton pump inhibitor therapy. With less than 36% of refractory symptoms associated with gastro-oesophageal reflux, gastric acid breakthrough cannot explain symptom refractoriness to proton pump inhibitor therapy in a significant majority of patients evaluated by 24-h pH study.
authors.affiliation: Gastroenterology and Hepatology, Mayo Clinic and Foundation, Rochester, MN 55905, USA. Nzeako.Ugochukwu@mayo.edu
authors.forename: U C
authors.initials: UC
authors.lastname: Nzeako
authors.forename: J A
authors.initials: JA
authors.lastname: Murray
mesh_terms: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000897:Anti-Ulcer Agents / Q000627:therapeutic use*; D002940:Circadian Rhythm; D004334:Drug Administration Schedule; D004791:Enzyme Inhibitors / Q000627:therapeutic use; D005260:Female; D005744:Gastric Acid / Q000378:metabolism*; D005745:Gastric Acidity Determination; D005764:Gastroesophageal Reflux / Q000188:drug therapy* / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D064747:Lansoprazole; D008297:Male; D008875:Middle Aged; D009853:Omeprazole / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D054328:Proton Pump Inhibitors; D017211:Treatment Failure
chemical_list: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000897:Anti-Ulcer Agents; D004791:Enzyme Inhibitors; D054328:Proton Pump Inhibitors; D064747:Lansoprazole; D009853:Omeprazole