Effect of laparoscopic sleeve gastrectomy versus laparoscopic Roux-en-Y gastric bypass on body composition

BackgroundThere is limited data with respect to body composition changes for laparoscopic sleeve gastrectomy (SG) and laparoscopic Roux-en-Y gastric bypass (RYGB). The objective of this study was to analyse changes in body composition between these two procedures during the first year after bariatric surgery.MethodsA prospective study was performed in patients undergoing bariatric surgery at two tertiary hospitals between 2017 and 2023. Body composition was assessed with dual-energy x-ray absorptiometry immediately before surgery, and at 1-, 6-, 12-, 18- and 24-months post-operatively, with a subgroup analysis performed for patients who undertook a scan at 18- and 24-months. Total weight loss (TWL), body mass index (BMI), fat mass (FM), lean body mass (LBM) and bone mineral content (BMC) parameters were compared between SG and RYGB.ResultsForty-five patients were included in this series (SG n = 30, RYGB n = 15). There was a significant reduction in mean %TWL of 26.94 +/- 8.86% and mean BMI of 11.12 +/- 3.70 kg/m2 over 12-months. LBM accounted for 17.8% of TWL over 12-months, SG and RYGB did not differ in terms of loss of FM or LBM. For both procedures, the loss of LBM appeared to plateau at 6-months post-operatively. The only statistically significant finding between the two procedures was that RYGB resulted in an additional 0.06 kg loss compared with SG.ConclusionSG and RYGB have been shown to have comparable weight loss and body composition changes in the short-to-medium term following surgery. LBM reduction was most significant in the early post-operative period across the entire cohort. This prospective study looks at longitudinal body composition changes for bariatric surgical patients. Lean body mass accounted for 17.8% of weight loss over 12-months, although these loss appeared to plateau at 6-months post-operatively. Furthermore, sleeve gastrectomy and roux en Y gastric bypass patients did not differ in terms of the loss of fat mass or lean body mass. image