Gastro-oesophageal reflux associated with nocturnal gastric acid breakthrough on proton pump inhibitors.

BACKGROUND: Nocturnal gastric acid breakthrough, defined as intragastric pH < 4 for more than 1 h in the overnight period, is observed in up to 70% of normal subjects on proton pump inhibitors taken twice daily. The frequency of this breakthrough in patients with gastro-oesophageal reflux and accompanying oesophageal reflux during this period has not been studied. AIM: To examine the frequency of nocturnal break-through and accompanying oesophageal acid exposure in patients with gastro-oesophageal reflux treated with proton pump inhibitors twice daily.
METHODS: Prolonged ambulatory pH records from 76 patients on twice daily proton pump inhibitors between January 1991 and July 1997 were analysed for the presence of nocturnal gastric acid breakthrough and accompanying oesophageal pH < 4. Studies from 31 normal subjects on twice daily proton pump inhibitors constituted the control group.
RESULTS: Nocturnal gastric acid breakthrough was seen in 70% of 61 patients with gastro-oesophageal reflux, 80% of 15 patients with Barrett's oesophagus and 67% of normal controls (P=N.S.). Oesophageal acid exposure was seen in 33% of gastro-oesophageal reflux patients, 50% of Barrett's oesophagus patients and 8% of normal controls (P < 0.03). No difference was found between patients taking omeprazole or lansoprazole.
CONCLUSION: Nocturnal acid breakthrough is frequently seen on proton pump inhibitors twice daily and is often accompanied by oesophageal reflux. This has important implications for medical therapy in patients with severe gastro-oesophageal reflux and Barrett's oesophagus.