title: Esophageal pH-impedance monitoring and symptom analysis in GERD: a study in patients off and on therapy.
abstract: BACKGROUND
  Combined esophageal pH-impedance monitoring allows detection of nearly all gastroesophageal reflux episodes, acid as well as nonacid. However, the role of nonacid reflux in the pathogenesis of symptoms is poorly known. The aim of this study was to evaluate the diagnostic yield of this technique in patients with suspected reflux symptoms while on or off PPI therapy.
  
  
  METHODS
  The recordings of 150 patients recruited at seven academic centers with symptoms possibly related to gastroesophageal reflux were analyzed. Reflux events were detected visually using impedance (Sandhill, CO) and then characterized by pHmetry as acid or nonacid reflux. The temporal relationship between symptoms and reflux episodes was analyzed: a symptom association probability (SAP) > or =95% was considered indicative of a positive association.
  
  
  RESULTS
  One hundred fifty patients were included, 102 women (mean age 52 +/- 14 yr, range 16-84). Among the 79 patients off PPI, five did not report any symptom during the recording period. A positive SAP was found in 41 of the 74 symptomatic patients (55.4%), including acid reflux in 23 (31.1%), nonacid reflux in three (4.1%), and acid and nonacid in 15 (20.3%). In the group of patients on PPI (N = 71, 46 women, mean age 51 +/- 15 yr), 11 were asymptomatic during the study, SAP was positive in 22 of the 60 symptomatic patients (36.7%), including acid reflux in three (5.0%), nonacid reflux in 10 (16.7%), and acid and nonacid in nine (15.0%). The symptoms most frequently associated with nonacid reflux were regurgitation and cough.
  
  
  CONCLUSIONS
  Adding impedance to pH monitoring improves the diagnostic yield and allows better symptom analysis than pHmetry alone, mainly in patients on PPI therapy. The impact of this improved diagnostic value on gastroesophageal reflux disease management remains to be investigated by outcome studies.
authors.affiliation: Gastroenterology Department, Saint André Hospital, Bordeaux, France.
authors.forename: Frank
authors.initials: F
authors.lastname: Zerbib
authors.forename: Sabine
authors.initials: S
authors.lastname: Roman
authors.forename: Alain
authors.initials: A
authors.lastname: Ropert
authors.forename: Stanislas Bruley
authors.initials: SB
authors.lastname: des Varannes
authors.forename: Philippe
authors.initials: P
authors.lastname: Pouderoux
authors.forename: Ulriikka
authors.initials: U
authors.lastname: Chaput
authors.forename: François
authors.initials: F
authors.lastname: Mion
authors.forename: Eric
authors.initials: E
authors.lastname: Vérin
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Galmiche
authors.forename: Daniel
authors.initials: D
authors.lastname: Sifrim
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004791:Enzyme Inhibitors / Q000627:therapeutic use*; D050782:Esophageal pH Monitoring; D005260:Female; D005500:Follow-Up Studies; D005744:Gastric Acid / Q000378:metabolism*; D005764:Gastroesophageal Reflux / Q000175:diagnosis* / Q000188:drug therapy / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D009853:Omeprazole / Q000627:therapeutic use*; D054328:Proton Pump Inhibitors; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012720:Severity of Illness Index
chemical_list: D004791:Enzyme Inhibitors; D054328:Proton Pump Inhibitors; D009853:Omeprazole