Original Contribution
The American Journal of Gastroenterology (2006) 101, 1956–1963; doi:10.1111/j.1572-0241.2006.00711.x
Esophageal pH-Impedance Monitoring and Symptom Analysis in GERD: A Study in Patients off and on Therapy
Frank Zerbib MD, PhD1, Sabine Roman MD2, Alain Ropert MD, PhD3, Stanislas Bruley des Varannes MD, PhD4, Philippe Pouderoux MD, PhD5, Ulriikka Chaput MD6, François Mion MD, PhD2, Eric Vérin MD, PhD6, Jean-Paul Galmiche MD, FRCP4 and Daniel Sifrim MD, PhD7
- 1Gastroenterology Department, Saint André Hospital, Bordeaux, France;
- 2Digestive Physiology Department, Edouard Herriot Hospital, Lyon, France
- 3Digestive Physiology Department, Pontchaillou Hospital, Rennes, France
- 4Digestive Diseases Institute, CIC-INSERM, Hôtel Dieu, Nantes, France
- 5Gastroenterology Department, Caremeau Hospital, Nîmes, France
- 6Digestive Physiology Department, Charles Nicolle Hospital, Rouen, France
- 7Center for Gastroenterological Research, Catholic University of Leuven, Leuven, Belgium
Correspondence: Frank Zerbib, MD, PhD, Gastroenterology Department, Saint Andre Hospital, 1, rue Jean Burguet, 33075 Bordeaux, France.
Received 11 February 2006; Accepted 4 April 2006.
Abstract
INTRODUCTION:
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.
PATIENTS AND 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) 
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.
CONCLUSION:
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.
