title: Preoperative assessment of gut hormones does not correlate to weight loss after Roux-en-Y gastric bypass surgery.
abstract: BACKGROUND
  Roux-en-Y gastric bypass (RYGB) surgery is an effective and frequently used surgical treatment for severe obesity. Postoperative weight loss varies markedly, but biomarkers to predict weight loss outcomes remain elusive. Levels of the satiety gut hormones glucagon like peptide-1 (GLP-1) and peptide YY (PYY) are attenuated in obese patients but elevated after RYGB surgery. We aimed to evaluate the preoperative responses of GLP-1 and PYY to a standard meal as a predictor of weight loss after RYGB surgery. We hypothesized that weak satiety gut hormone responses preoperatively, would predict poor weight loss after RYGB surgery.
  
  
  METHODS
  Preoperatively 43 patients (F = 25/M = 18) had GLP-1 and PYY measured in the fasting state and at 30-minute intervals over 180 minutes after a standard 400 kcal mixed meal. Weight loss was assessed at weight stability after surgery (mean 16.2 mo [CI 15.516.9]).
  
  
  RESULTS
  Body mass index decreased from 44.0 kg/m(2) (CI 42.2-45.7) before surgery to 30.3 kg/m(2) (CI 28.4-32.2) after surgery (P<.001). Preoperative GLP-1 and PYY responses to food intake; as delta value between fasting and maximum as well as total responses during 180 minutes did not correlate to total weight loss (GLP-1; rho = .060 and rho = -.089, PYY; rho = -.03 and rho = -.022, respectively) or to excess weight loss % (GLP-1; rho = .051 and rho = -.064, PYY; rho = -.1 and rho = -.088, respectively).
  
  
  CONCLUSIONS
  Preoperative responses of GLP-1 and PYY to a 400 kcal mixed meal do not correlate to postoperative weight loss after RYGB surgery for morbid obesity.
authors.affiliation: Department of Gastrosurgical Research and Education, Sahlgrenska Academy, University of Gothenburg, Department of surgery, Sahlgrenska University Hospital/Sahlgrenska, Gothenburg, Sweden. Electronic address: malin.werling@gmail.com.
authors.forename: Malin
authors.initials: M
authors.lastname: Werling
authors.affiliation: Department of Gastrosurgical Research and Education, Sahlgrenska Academy, University of Gothenburg, Department of surgery, Sahlgrenska University Hospital/Sahlgrenska, Gothenburg, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Fändriks
authors.affiliation: Clinical Biochemistry, King's College Hospital NHS Foundation Trust, London, United Kingdom.
authors.forename: Royce P
authors.initials: RP
authors.lastname: Vincent
authors.forename: Vincent P
authors.initials: VP
authors.lastname: Royce
authors.affiliation: Clinical Biochemistry, King's College Hospital NHS Foundation Trust, London, United Kingdom.
authors.forename: Gemma F
authors.initials: GF
authors.lastname: Cross
authors.affiliation: Department of Gastrosurgical Research and Education, Sahlgrenska Academy, University of Gothenburg, Department of surgery, Sahlgrenska University Hospital/Sahlgrenska, Gothenburg, Sweden; Diabetes Complications Research Centre, Conway Institute, University College Dublin, Ireland; Investigative Science, Imperial College London, United Kingdom.
authors.forename: Carel W
authors.initials: CW
authors.lastname: le Roux
authors.affiliation: Department of Gastrosurgical Research and Education, Sahlgrenska Academy, University of Gothenburg, Department of surgery, Sahlgrenska University Hospital/Sahlgrenska, Gothenburg, Sweden.
authors.forename: Torsten
authors.initials: T
authors.lastname: Olbers
mesh_terms: D000328:Adult; D019540:Area Under Curve; D015992:Body Mass Index; D005260:Female; D015390:Gastric Bypass / Q000379:methods*; D052216:Glucagon-Like Peptide 1 / Q000378:metabolism*; D006801:Humans; D010535:Laparoscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000503:physiopathology / Q000601:surgery*; D019894:Peptide YY / Q000378:metabolism*; D011300:Preoperative Care / Q000379:methods; D011446:Prospective Studies; D015431:Weight Loss / Q000502:physiology
chemical_list: D019894:Peptide YY; D052216:Glucagon-Like Peptide 1
keywords: Bariatric surgery; GLP-1; Gastric bypass; Gastrointestinal hormones; Glucagon like peptide-1; Obesity; Outcome assessment (Healthcare); PYY; Peptide YY; Predictive factor; Predictive value of tests; Weight change; Weight loss