Impact of Preoperative Weight Loss on 30-Day Complication Rate after Bariatric Surgery.

Background: The aim of this study is to evaluate the impact of preoperative weight loss on surgical outcomes and operating room (OR) times after primary bariatric procedures, including laparoscopic sleeve gastrectomy (LSG) and laparoscopic Roux-en-Y gastric bypass (RYGB).

Study Design: A retrospective cohort study uses the 2021 MBSAQIP dataset. Preoperative total weight loss (TWL)% was calculated. Patients were then divided in to 4 groups: those with no weight loss, lost <0 to <5%, lost ≥5% to <10%, or lost ≥10% TWL preoperatively. These groups were then stratified into those with BMI less than 50 kg/m 2 and those with BMI 50 kg/m 2 or more and 30-day outcomes and OR times were compared.

Results: Analysis included 171,010 patients. For BMI less than 50 kg/m 2 , preoperative weight loss led to no consistent improvement in surgical outcomes. Although >0% to <5% TWL led to a decrease in intra- and postoperative occurrences after RYGB and a decrease in reoperation rates after LSG, these observations were not seen in those with higher degree of weight loss. In patients with BMI 50 kg/m 2 or more, preoperative weight loss showed a consistent improvement in reintervention rates after LSG, and readmission rates after RYGB. There was no improvement in other outcomes, however, irrespective of degree of preoperative weight loss.

Conclusions: In patients undergoing primary bariatric surgery, preoperative weight loss does not lead to a consistent improvement in outcomes or OR times. In those with BMI 50 kg/m 2 or more, there may be improvement in select outcomes that is procedure-specific. Overall, these data do not support a uniform policy of preoperative weight loss, although selective use in some high-risk patients may be appropriate.