Background:
The demand for conversion bypass bariatric procedures has increased, however the ideal procedure remains contentious. The aim of this study was to determine if there is a significant difference in weight loss outcomes between conversion Roux-en-Y gastric bypass (RYGB) compared to Single Anastomosis Gastric Bypass (SAGB).
Design:
Single-centre retrospective cohort analysis of prospectively maintained patient records. The primary outcome measure was the annual weight loss trends from 12 months to 5 years following conversion to RYGB versus SAGB.
Participants: 251 adult patients who received government funded conversion gastric bypass surgery between 01/01/2013 and 30/04/2023 were eligible for inclusion.
Results: Difference in median percentage total weight loss (%TWL) between RYGB and SAGB at repeated measures from one to five years post conversion was only statistically significantly at 2years, χ2(1) = 4.0, p= 0.045. However, when the type of primary metabolic surgery was considered, participants who received a conversion RYGB from laparoscopic adjustable gastric banding (LAGB) demonstrated statistically significantly better annual %TBWL out to 5years compared to those who had received a prior sleeve gastrectomy (LSG), χ2(1) = 6.4, p= 0.011. Comparatively there was no statistically significant difference in 5 year %TBWL in patients who were converted to SAGB from either LAGB or LSG, χ2(1) = 1.6, p= 0.201.
Conclusion:
Both RYGB and SAGB provide durable medium term weight loss when performed as conversion procedures. Our results suggest that significantly better medium term weight loss can be achieved in participants who undergo conversion RYGB if they have previously received LAGB.