title: Can acid (pH) refluxes predict multichannel intraluminal impedance refluxes? A correlation study.
abstract: OBJECTIVE
  The present study aims to explore if and when acid (pH) refluxes can predict refluxes detected by multichannel intraluminal impedance (MII) studies. This correlation may indicate whether pH probe-only and MII-pH studies are interchangeable.
  
  
  METHODS
  Prospective observational cross sectional study of symptomatic children (below 18 years) who had MII-pH studies done for gastroesophageal reflux. Clinical data were extracted from patient records. Non-parametric tests, Pearson's rho and receiver operating characteristic (ROC) curves were used for data analysis.
  
  
  RESULTS
  A total of 153 children were included in the study and 62% were on acid suppression. Indices for acid and MII refluxes correlated with each other only in those without acid suppression. This correlation was lost in children on acid suppression. There was no statistically significant difference in acid or MII reflux indices in children with or without acid suppression. Like acid reflux, indices for MII refluxes had good correlation with each other irrespective of acid suppression. Liquid and mixed MII refluxes showed excellent correlation with respective types of proximally migrating refluxes. The values for MII reflux indices derived from our patient population were in broad agreement with available pediatric and adult data.
  
  
  CONCLUSIONS
  A pH probe-only study in patients without acid suppression may reflect both acid and volume (MII) reflux activities adequately and can substitute for MII-pH study. The observed excellent correlation between acid and MII refluxes with proximal migration may justify using pH probe-only studies for extra esophageal symptoms in patients without acid suppression.
authors.affiliation: Division of Gastroenterology, Children's Medical Center, Medical College of Georgia, Augusta, Georgia 309012, USA. smisra@mail.mcg.edu
authors.forename: Sudipta
authors.initials: S
authors.lastname: Misra
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D017097:Electric Impedance; D050782:Esophageal pH Monitoring / Q000295:instrumentation; D005764:Gastroesophageal Reflux / Q000150:complications / Q000175:diagnosis* / Q000188:drug therapy; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007223:Infant; D011237:Predictive Value of Tests; D011446:Prospective Studies; D054328:Proton Pump Inhibitors / Q000627:therapeutic use; D012372:ROC Curve
chemical_list: D054328:Proton Pump Inhibitors