title: Diagnostic interpretation of 24-hour intragastric pH-metry using a pattern recognition method.
abstract: BACKGROUND
  Intragastric pH-metry is a widely used method in the evaluation of gastric acidity, but the interpretation of these data is not standardized.
  
  
  METHODS
  The pH-metry data of 60 patients were sorted retrospectively into three groups according to the maximal acid output (MAO) values measured after stimulation by pentagastrin: hypoacid group (MAO < 5 mmol/h, n = 17), normacid group (MAO 10-15 mmol/h, n = 18) and superacid group (MAO > 25 mmol/h, n = 25). Statistical effectiveness of several descriptive statistical values and predefined time-intervals in differentiation between the study groups was analysed by the pattern recognition by independent multicategory analysis (PRIMA) method.
  
  
  RESULTS
  The mean pH, the integrated pH and the time-interval of pH > or = 3 values were the most effective parameters for discriminating between each pair of groups. Hypoacid-normacid-superacid: mean pH 6.1 +/- 0.2-4.2 +/- 0.23-1.5 +/- 0.07; integrated pH 8898 +/- 208-5987 +/- 339-2224 +/- 98 pH.min; and pH > or = 3 1440 +/- 0-392 +/- 44-80 +/- 11 min, respectively (+/- SEM). More than a 99.9% separation of the study groups was achieved using these three parameters concomitantly by the PRIMA method, even when comparing 6-h daytime periods of measurements. A relative disagreement was found when reclassifying the hypoacid and normacid patients on the basis of pH records, compared with the primary classification based on the MAO data (11 out of 35 patients, 31%).
  
  
  CONCLUSIONS
  The analysis of the mean pH data (instead of medians or [H+]), the AUC-pH and the pH > or = 3 duration, either separately or most beneficially concomitantly, are recommended for the diagnostic interpretation of intragastric pH-metry data. The duration of the diagnostic intragastric pH-metry measurements might be decreased to 6 h by using the PRIMA method.
authors.affiliation: First Department of Medicine, Medical University of Pécs, Hungary.
authors.forename: B
authors.initials: B
authors.lastname: Hunyady
authors.forename: I
authors.initials: I
authors.lastname: Juricskay
authors.forename: F
authors.initials: F
authors.lastname: Pakodi
authors.forename: C
authors.initials: C
authors.lastname: Horváth
authors.forename: G
authors.initials: G
authors.lastname: Mózsik
mesh_terms: D005744:Gastric Acid / Q000378:metabolism; D005745:Gastric Acidity Determination / Q000295:instrumentation*; D006801:Humans; D015233:Models, Statistical; D010363:Pattern Recognition, Automated; D010418:Pentagastrin / Q000494:pharmacology; D012016:Reference Values; D012189:Retrospective Studies
chemical_list: D010418:Pentagastrin