Weight loss before gastric bypass: feasibility and effect on postoperative weight loss and weight loss maintenance.

Background: This study was performed at a tertiary care university hospital. We hypothesized that weight loss before laparoscopic Roux-en-Y gastric bypass (LRYGB) is feasible, does not diminish the expected postoperative weight loss, and might enhance overall weight loss and maintenance.

Methods: A population of 351 consecutive patients, who had undergone LRYGB, was divided into 4 groups depending on the percentage of body weight loss achieved before surgery (group 1, none or gain; group 2, <5%; group 3, 5-10%; and group 4, >10%). Data were collected regarding the demographics, body mass index (BMI) change, and excess weight loss and analyzed by analysis of variance and Fisher's exact test at the alpha = 0.05 level.

Results: All groups were demographically similar in age and were predominantly women. The maximal follow-up was 36 months. Groups 3 and 4 had significantly greater initial excess weight and BMI (P <.05) but these became similar after the preoperative weight loss. Most patients (74%) were able to lose weight before surgery, with 36% losing >5% body weight. Preoperative weight loss did not decrease the magnitude of the expected postoperative weight loss. Patients who lost weight preoperatively demonstrated more excess weight loss and BMI change (from their initial weight) that was sustained far into the postoperative period and reached statistical significance at several points (P <.05).

Conclusion: The results of this study have demonstrated that obese patients are capable of losing weight before LRYGB and that this weight loss does not negatively affect their expected postoperative weight loss. Furthermore, preoperative weight loss combined with LRYGB might result in better long-term excess weight loss and BMI change than surgery alone.