Beyond Restrictive: Sleeve Gastrectomy to Single Anastomosis Duodeno-Ileal Bypass with Sleeve Gastrectomy as a Spectrum of One Single Procedure

Introduction: Single anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S) is a restrictive/hypoabsorptive procedure recommended for patients with obesity class 3. For safety reasons, SADI-S can be split into a two-step procedure by performing a sleeve gastrectomy (SG) first. This stepwise approach also provides an unprecedented opportunity to disentangle the weight loss mechanisms triggered by each component. The objective was to compare weight trajectories and post-prandial endocrine and metabolic responses of patients with obesity class 3 submitted to SADI-S or SG as the first step of SADI-S. Methods: Subjects submitted to SADI-S (n = 7) or SG (n = 7) at a tertiary referral public academic hospital underwent anthropometric evaluation and a liquid mixed meal tolerance test (MMTT) pre-operatively and at 3, 6, and 12 months post-operatively. Results: Anthropometric parameters, as well as metabolic and micronutrient profiles, were not significantly different between groups, neither before nor after surgery. There were no significant differences in fasting or post-prandial glucose, insulin, C-peptide, ghrelin, insulin secretion rate, and insulin clearance during the MMTT between subjects submitted to SADI-S and SG. There was no lost to follow-up. Conclusions: The restrictive component seems to be the main driver for weight loss and metabolic adaptations observed during the first 12 months after SADI-S, given that the weight trajectories and metabolic profiles do not differ from SG. These data provide support for surgeons' choice of a two-step SADI-S without jeopardizing the weight loss outcomes.