Day-to-day discrepancy in Bravo pH monitoring is related to the degree of deterioration of the lower esophageal sphincter and severity of reflux disease

BACKGROUND: The Bravo capsule allows monitoring of esophageal acid exposure over a two-day period. Experience has shown that 24–32% of patients will have abnormal esophageal acid exposure detected on only one of the 2 days monitored. This variation has been explained by the effect of endoscopy and sedation. The aim of this study was to assess the day-to-day discrepancy following transnasal placement of the Bravo capsule without endoscopy or sedation and to determine factors related to this variability. METHODS: Bravo pH monitoring was performed by transnasal placement of the capsule in 310 patients. Patients were divided into groups based on the composite pH score: both days normal, both days abnormal and only one of the 2 days abnormal. Lower esophageal sphincter (LES) characteristics were compared between groups. RESULTS: Of the 310 patients evaluated, 60 (19%) showed a discrepancy between the 2 days. A total of 127 patients had a normal pH score on both days and 123 had an abnormal pH score on both days. Of the 60 patients with a discrepancy, 27 were abnormal the first day and 33 (55%) were abnormal the second day. Patients with abnormal esophageal acid exposure on both days had higher degrees of esophageal acid exposure and were more likely to have a defective LES compared to those with an abnormal score on only one day (35 vs. 83%, p = 0.027). CONCLUSION: Patients with a discrepancy between days of Bravo pH monitoring have lower esophageal acid exposure. Variability between the 2 days represents early deterioration of the gastroesophageal barrier and indicates less advanced reflux disease.