title: The impact of preoperative weight loss in patients undergoing laparoscopic Roux-en-Y gastric bypass.
abstract: BACKGROUND
  Laparoscopic Roux-en-Y gastric bypass (LRYGBP) is a widely performed bariatric operation. Preoperative factors that predict successful outcomes are currently being studied. The goal of this study was to determine if preoperative weight loss was associated with positive outcomes in patients undergoing LRYGBP.
  
  
  METHODS
  A retrospective analysis was performed of all patients undergoing LRYGBP at our institution between July 2002 (when a policy of preoperative weight loss was instituted) and August 2003. Outcome measures evaluated at 1 year postoperatively included percent excess weight loss (EWL) and correction of co-morbidities. Statistical analysis was performed by multiple linear regression. P<0.05 was considered significant.
  
  
  RESULTS
  The study included 90 subjects. Initial BMI ranged from 35.4 to 63.1 (mean 48.1). Preoperative weight loss ranged from 0 to 23.8% (mean 7.25). At 12 months, postoperative EWL ranged from 40.4% to 110.9 % (mean 74.4%). Preoperative loss of 1% of initial weight correlated with an increase of 1.8% of postoperative EWL at 1 year. In addition, initial BMI correlated negatively with EWL, so that an increase of 1 unit of BMI correlated with a decrease of 1.34% of EWL. Finally, preoperative weight loss of >5% correlated significantly with shorter operative times by 36 minutes. Preoperative weight loss did not correlate with postoperative complications or correction of co-morbidities.
  
  
  CONCLUSIONS
  Preoperative weight loss resulted in higher postoperative weight loss at 1 year and in shorter operative times with LRYGBP. No differences in correction of co-morbidities or complication rates were found with preoperative weight loss in this study. Preoperative weight loss should be encouraged in patients undergoing bariatric surgery.
authors.affiliation: Department of Surgery, Stanford University School of Medicine 94305, and VA Palo Alto Health Care System, Palo Alto, CA, USA.
authors.forename: R
authors.initials: R
authors.lastname: Alvarado
authors.forename: R S
authors.initials: RS
authors.lastname: Alami
authors.forename: G
authors.initials: G
authors.lastname: Hsu
authors.forename: B Y
authors.initials: BY
authors.lastname: Safadi
authors.forename: B R
authors.initials: BR
authors.lastname: Sanchez
authors.forename: J M
authors.initials: JM
authors.lastname: Morton
authors.forename: M J
authors.initials: MJ
authors.lastname: Curet
mesh_terms: D000328:Adult; D000713:Anastomosis, Roux-en-Y; D005260:Female; D015390:Gastric Bypass / Q000379:methods; D006801:Humans; D007431:Intraoperative Complications; D010535:Laparoscopy; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000150:complications / Q000601:surgery* / Q000628:therapy; D011183:Postoperative Complications; D015431:Weight Loss