title: Children with cystic fibrosis have prolonged chemical clearance of acid reflux compared to symptomatic children without cystic fibrosis.
abstract: OBJECTIVE
  Few studies compare gastroesophageal reflux (GER) parameters of cystic fibrosis (CF) children and symptomatic non-CF children. We aimed to compare the impedance-pH (IMP-pH) parameters for these two groups and to test the hypothesis that prolonged acid exposure in CF patients is due to delayed chemical clearance (CC).
  
  
  METHODS
  IMP-pH tracings from 16 CF children (median 8.2 years) and 16 symptomatic non-CF children (median 8.3 years) were analyzed. Software was used to generate IMP-pH reports and parameter data were extracted. IMP-pH was used to calculate the mean CC for each patient.
  
  
  RESULTS
  pH studies showed no difference in acid GER (AGER) frequency (p = 0.587); however, mean AGER duration, duration of longest AGER, AGER index, and DeMeester scores were all significantly higher for CF patients. IMP showed no difference in GER frequency [neither acidic (p = 0.918) nor non-acidic (p = 0.277)], but total bolus clearance was more efficient in CF patients (p = 0.049). A larger percentage of total GER reached the proximal esophagus in non-CF children (p = 0.039). Analyses of two-phase AGER episodes showed that these events were more acidic (p = 0.003) and the CC phase was significantly prolonged in the CF cohort (p = 0.001).
  
  
  CONCLUSIONS
  Compared to symptomatic non-CF children, CF children do not have more frequent reflux. Actually, they have better bolus clearance efficiency following reflux and may even have better control over the number of GER episodes that reach the proximal esophagus. CC of AGER, however, is significantly prolonged in the CF cohort, likely due to hyperacidity of refluxed gastric contents.
authors.affiliation: Division of Gastroenterology, Hepatology, and Nutrition, Nationwide Children's Hospital, Columbus, OH, USA, frederick.woodley@nationwidechildrens.org.
authors.forename: Frederick W
authors.initials: FW
authors.lastname: Woodley
authors.forename: Rodrigo S
authors.initials: RS
authors.lastname: Machado
authors.forename: Don
authors.initials: D
authors.lastname: Hayes
authors.forename: Carlo
authors.initials: C
authors.lastname: Di Lorenzo
authors.forename: Ajay
authors.initials: A
authors.lastname: Kaul
authors.forename: Beth
authors.initials: B
authors.lastname: Skaggs
authors.forename: Karen
authors.initials: K
authors.lastname: McCoy
authors.forename: Alpa
authors.initials: A
authors.lastname: Patel
authors.forename: Hayat
authors.initials: H
authors.lastname: Mousa
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003550:Cystic Fibrosis / Q000150:complications / Q000503:physiopathology*; D050782:Esophageal pH Monitoring; D005260:Female; D005764:Gastroesophageal Reflux / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D008297:Male; D010992:Plethysmography, Impedance; D013997:Time Factors