Time esophageal pH < 4 overestimates the prevalence of pathologic esophageal reflux in subjects with gastroesophageal reflux disease treated with proton pump inhibitors.
BACKGROUND
A Stanford University study reported that in asymptomatic GERD patients who were being treated with a proton pump inhibitor (PPI), 50% had pathologic esophageal acid exposure.


OBJECTIVE
We considered the possibility that the high prevalence of pathologic esophageal reflux might simply have resulted from calculating acidity as time pH < 4.


METHODS
We calculated integrated acidity and time pH < 4 from the 49 recordings of 24-hour gastric and esophageal pH from the Stanford study as well as from another study of 57 GERD subjects, 26 of whom were treated for 8 days with 20 mg omeprazole or 20 mg rabeprazole in a 2-way crossover fashion.


RESULTS
The prevalence of pathologic 24-hour esophageal reflux in both studies was significantly higher when measured as time pH < 4 than when measured as integrated acidity. This difference was entirely attributable to a difference between the two measures during the nocturnal period. Nocturnal gastric acid breakthrough was not a useful predictor of pathologic nocturnal esophageal reflux.


CONCLUSIONS
In GERD subjects treated with a PPI, measuring time esophageal pH < 4 will significantly overestimate the prevalence of pathologic esophageal acid exposure over 24 hours and during the nocturnal period.
Gerson
Lauren B
LB
Stanford University School of Medicine, Stanford, CA, USA. lgerson@stanfordmed.org
Triadafilopoulos
George
G
Sahbaie
Peyman
P
Young
Winston
W
Sloan
Sheldon
S
Robinson
Malcolm
M
Miner
Philip B
PB
Gardner
Jerry D
JD
D053799:2-Pyridinylmethylsulfinylbenzimidazoles / Q000627:therapeutic use; D002940:Circadian Rhythm / Q000502:physiology*; D050782:Esophageal pH Monitoring; D004947:Esophagus / Q000503:physiopathology*; D005764:Gastroesophageal Reflux / Q000150:complications* / Q000188:drug therapy* / Q000209:etiology* / Q000503:physiopathology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009853:Omeprazole / Q000627:therapeutic use; D011237:Predictive Value of Tests; D015995:Prevalence; D054328:Proton Pump Inhibitors / Q000627:therapeutic use*; D064750:Rabeprazole; D012189:Retrospective Studies
D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D054328:Proton Pump Inhibitors; D064750:Rabeprazole; D009853:Omeprazole