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 pre-operative weight loss on surgical outcomes and 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 utilizing the 2021 MBSAQIP dataset. Pre-operative total weight loss (TWL)% was calculated. Patients were then divided in to 4 groups: those with no weight loss, lost 0<-<5%, lost 5%≤–<10%, or lost ≥10% TWL preoperatively. These groups were then stratified into those with BMI<50 and those with BMI ≥50 and 30-day outcomes and OR times were compared. Results: Analysis included 171,010 patients. For BMI<50, pre-operative weight loss led to no consistent improvement in surgical outcomes. While 0<-<5% TWL, led to a decrease in intra- and post- operative occurrences after RYGB, and a decrease in re-operation rates after LSG, these observations were not seen in those with higher degree of weight loss. In patients with BMI≥50, pre-operative weight loss showed a consistent improvement in re-intervention rates after LSG, and readmission rates after RYGB. There was no improvement in other outcomes however, irrespective of degree of pre-operative weight loss. Conclusion: In patients undergoing primary bariatric surgery, pre-operative weight loss does not lead to a consistent improvement in outcomes or OR times. In those with BMI≥50 there may be improvement in select outcomes that is procedure specific. Overall, this data does not support a uniform policy of pre-operative weight loss, although selective use in some high-risk patients may be appropriate.