Prospective Study of Gut Hormone and Metabolic Changes After Adjustable Gastric Banding and Roux-en-Y Gastric Bypass

Objective The objective of this study was to quantify hormones that regulate energy and glucose homeostasis in order to establish possible mechanisms for the greater efficacy of Roux-en-Y gastric bypass (RYGB) compared with laparascopic adjustable gastric banding (LAGB) in achieving weight loss and improved insulin sensitivity. Design Longitudinal study of patients undergoing LAGB (n=15) and RYGB (n=28) who were studied prior to surgery and at 2, 12, 26 and 52 wks afterwards. Measurements Fasting blood samples were drawn at each visit. Postprandial blood samples were also obtained prior to surgery and at 26 and 52 wks. Samples were assayed for peptide YY (PYY), ghrelin, glucagon-like peptide-1 (GLP-1), glucose, insulin, leptin, thyrotropic hormone (TSH), free T4 and free T3. Results At one year there was greater weight loss in RYGB compared with LAGB patients (30% vs 15%), but final body mass index was similar (34 vs 33 kg/m2). At wk 52, area under the curve (AUC) for PYY in RYGB subjects was greater than LAGB (P