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.
Dr Frank Zerbib and colleagues from Belgium evaluated the diagnostic yield of this technique in patients with suspected reflux symptoms.
The investigative team assessed the patients while on or off proton pump inhibitor (PPI) therapy.
The recordings of 150 patients recruited at 7 academic centers with symptoms possibly related to gastroesophageal reflux were analyzed.
The team detected reflux events visually using impedance and then characterized by pHmetry as acid or nonacid reflux.
|Symptom association probability was positive in 37%|
|American Journal of Gastroenterology|
The investigators analyzed the temporal relationship between symptoms and reflux episodes.
A symptom association probability of 95% or more was considered indicative of a positive association.
Among the 79 patients off PPI, the team noted that 5 did not report any symptom during the recording period.
The team found a positive symptom association probability in 55% of symptomatic patients.
The investigators found that 31% had acid reflux, 4% had nonacid reflux, and 20% had acid and nonacid.
In the group of patients on PPI, 11 were asymptomatic during the study, and symptom association probability was positive in 37% of symptomatic patients.
The team observed that in these patients acid reflux occurred in 5%, nonacid reflux in 17%, and acid and nonacid in 15%.
The symptoms most frequently associated with nonacid reflux were regurgitation and cough.
Dr Zerbib's team concludes, “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.”