title: Prolonged, wireless pH-studies have a high diagnostic yield in patients with reflux symptoms and negative 24-h catheter-based pH-studies.
abstract: BACKGROUND
  Catheter-based esophageal pH-monitoring is used to evaluate patients with suspected gastro-esophageal reflux disease (GERD); however false-negative results may occur due to poor tolerance of the catheter with reduced oral intake and activity, or high day-to-day variation in reflux and symptom events. We assessed diagnostic yield and clinical impact of prolonged, wireless pH-monitoring in patients with negative results from 24-h catheter-based studies and ongoing symptoms.
  
  
  METHODS
  Esophageal acid exposure (percentage time pH <4), Symptom Index, and Symptom Association Probability (SAP) were calculated. Diagnostic yield was assessed using Average (mean) and Worst Day (24-h period with highest acid exposure or symptom load) analyses. Outcome data were assessed 6-36 months (median 24) after initiation of definitive therapy based on physiologic testing.
  
  
  RESULTS
  Data from prolonged pH-monitoring up to 96-h (median 72-h) were available from 38 patients. Using Average and Worst Day analysis, esophageal acid exposure was pathologic in 37% and 47%, whereas SAP was positive in 34% and 63% of patients, respectively. Overall using Average and Worst Day analyses, 61% and 76% patients were diagnosed with GERD based on either pathologic acid exposure or positive symptom association. Of 12 patients that underwent antireflux surgery, 10(83%) reported a good outcome at a median 24 months follow-up.
  
  
  CONCLUSIONS
  Prolonged, wireless pH-monitoring increases test sensitivity and diagnostic yield in patients with continuing esophageal symptoms despite negative 24-h catheter-based pH-studies. Without a definitive diagnosis, many would not have received effective treatment.
authors.affiliation: Guy's and St Thomas' Hospitals, London, UK.
authors.forename: R
authors.initials: R
authors.lastname: Sweis
authors.forename: M
authors.initials: M
authors.lastname: Fox
authors.forename: A
authors.initials: A
authors.lastname: Anggiansah
authors.forename: T
authors.initials: T
authors.lastname: Wong
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D057785:Catheters; D050782:Esophageal pH Monitoring; D005260:Female; D005764:Gastroesophageal Reflux / Q000175:diagnosis* / Q000503:physiopathology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D055815:Young Adult