Value of 96-hour ambulatory esophageal pH monitoring in the assessment of patients with refractory acid reflux symptoms and their response to anti-reflux diet.

Ambulatory esophageal pH monitoring is a diagnostic tool in patients with heartburn and regurgitation. The aim of this study is to evaluate 96-hour esophageal pH monitoring in patients with gastroesophageal reflux disease (GERD), at baseline and under diet that impedes GER. We hypothesized that diet would potentially reduce pathologic acid exposure time (AET). Retrospective series of 88 patients with GERD undergoing wireless 96-hour pH monitoring. Two-day (48 hours) tandem periods, one on liberal, followed by another on restricted diet assessed esophageal AET. Primary end point was >30% reduction in AET while on anti-GER diet. Of the 88 patients, 16 were excluded because of probe migration. Endoscopy and biopsies assessed erosive esophagitis (EE) and Barrett's esophagus (BE), or normal esophagus. Abnormal AET (% pH < 4.0 ≥ 6) further defined nonerosive reflux disease (NERD), whereas normal AET (% pH < 4.0 < 6) with normal endoscopy defined patients as functional heartburn (FH). There were 6 patients with EE (n = 5) and BE (n = 1), 23 with NERD and 43 with FH. Anti-GER diet led to >30% reduction in AET in EE and NERD patients, but not in those with FH. Most patients (n = 43/72; 60%) had FH and could have avoided acid suppression. Furthermore, (14/23; 61%) of patients with NERD completely normalized AET with diet, potentially negating acid suppression. Ninety-six-hour esophageal pH distinguishes GERD patients from those with FH. Fifty percent of EE/BE patients and 61% of those with NERD completely normalize AET with diet. If pathologic AET occurs despite diet, acid suppression is indicated.