24-HOUR PH MEASUREMENTS IN MORBID-OBESITY - EFFECTS OF MASSIVE OVERWEIGHT, WEIGHT-LOSS AND GASTRIC DISTENSION

Objective: To investigate the influence of untreated (super)morbid obe sity and the effects of massive weight loss and chronic gastric disten sion on gastro-oesophageal reflux. Patients and methods: Seventeen you ng morbidly obese patients (32 years old; body weight 166.5 kg; body m ass index 55 kg/m(2)) underwent 24-h ambulatory oesophageal pH monitor ing before weight reduction and 4 months after treatment with energy-r estricted diet, physical exercise and intragastric balloon or sham pla cement in a randomized, double-blind design. To minimize bias, both 24 -h pH measurements were performed under similar conditions and dietary intake, and patients were matched for age, sex, body weight and body mass index. Results: At the start, group median data for the fraction of total time, time upright and time supine with pH less than 4 were w ithin normal limits. After a major median weight loss of 38.8 kg in 4 months these parameters did not change. On an individual basis, five o ut of 17 patients had pathological acid reflux prior to weight loss. T his reversed to normal in three subjects, but remained abnormal in two and became abnormal in one patient. The weight loss (58.4 kg) of thos e remaining or becoming acid refluxers was significantly different (P< 0.01) from those with normal or normalizing pH measurements (36.9 kg). A 4-month period of gastric distension by a 500 mi balloon did not in fluence acid reflux parameters. Conclusion: The influence of untreated (super)morbid obesity on acid reflux was less pronounced than expecte d. There was also no major adverse effect of chronic gastric distensio n. Only excessive weight loss (i.e. 58 kg) appeared to have an untowar d effect on acid reflux.