Preoperative weight loss before bariatric surgery.

HYPOTHESIS: Preoperative weight loss reduces the frequency of surgical complications in patients undergoing bariatric surgery. DESIGN: Review of records of patients undergoing open or laparoscopic gastric bypass. SETTING: A comprehensive, multidisciplinary obesity treatment center at a tertiary referral center that serves central Pennsylvania. PATIENTS: A total of 881 patients undergoing open or laparoscopic gastric bypass from May 31, 2002, through February 24, 2006. INTERVENTION: All preoperative patients completed a 6-month multidisciplinary program that encouraged a 10% preoperative weight loss. MAIN OUTCOME MEASURES: Loss of excess body weight (EBW) and total and major complication rates. RESULTS: Of the 881 patients, 592 (67.2%) lost 5% or more EBW and 423 (48.0%) lost more than 10% EBW. Patients referred for open gastric bypass (n = 466) were generally older (P < .001), had a higher body mass index (P < .001), and were more often men (P < .001) than those undergoing laparoscopic gastric bypass (n = 415). Total and major complication rates were higher in patients undergoing open gastric bypass (P < .001 and P = .03, respectively). Univariate analysis revealed that increasing preoperative weight loss is associated with reduced complication frequencies for the entire group for total complications (P =.004) and most likely for major complications (P = .06). Controlling for age, sex, baseline body mass index, and type of surgery in a multiple logistic regression model, increased preoperative weight loss was a predictor of reduced complications for any (P =.004) and major (P = .03) complications. CONCLUSION: Preoperative weight loss is associated with fewer complications after gastric bypass surgery.