Outcomes of Single Anastomosis Duodeno-Ileal Bypass With Sleeve Gastrectomy (SADI-S): A Single Bariatric Center Experience

Abstract

Introduction Bariatric surgery is increasingly employed to address the global burden of morbid obesity, with Roux-en-Y gastric bypass (RYGB) representing the predominant procedure. However, some patients, particularly those with extreme obesity (BMI >50 kg/m²), may experience unsatisfactory weight-related outcomes following RYGB. While biliopancreatic diversion with duodenal switch (BPD-DS) offers superior weight reduction for this population, its complexity and associated risks limit its widespread use. Single anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S) was developed as a simpler substitue to BPD-DS, aiming to gain equivalent weight loss with improved safety profile. This analysis examined the efficacy of SADI-S in facilitating weight loss and ameliorating concomitant conditions (type 2 diabetes mellitus, hypertension, and obstructive sleep apnea) at various time points up to nine years post-procedure. Additionally, the study assessed the incidence of nutritional deficiencies following SADI-S. Material and methods This retrospective analysis utilized data obtained from patients undergoing SADI-S at a high-volume specialized bariatric centre between January 2016 and December 2022. Inclusion criteria encompassed individuals with high BMI and uncontrolled obesity-related comorbidities who had experienced insufficient weight-related outcomes following a previous bariatric surgery and demonstrated good compliance within a Tier 3 weight management program. Patients were excluded if they were non-compliant, unfit for surgery, or under 18 years old. Participants were followed up quarterly in the first year, every four months in the second year, and yearly thereafter. Nutritional assessments were performed in accordance with British Obesity and Metabolic Surgery Society (BOMSS) guidelines. Relevant data were extracted from patient clinical records and institutional electronic databases and analyzed using Microsoft Excel. Results There were 4000+ bariatric procedures conducted during this time. Seventeen patients were deemed as suitable candidates for SADI-S after multidisciplinary team discussion. The surgeries were performed by various surgeons. Most participants were women, with an age range of 23 to 64 years. The median BMI was 63.4 kg/m² (range: 35 kg/m² to 96.2 kg/m²). Mean percentage excess weight loss (%EWL) was 32% (range: 15% to 53%) at six months, 69.6% (range: 34% to 90%) at one year, and 86.2% (range: 43% to 109%) at two years post-procedure. Extended follow-up data (six to nine years) were available for 16 patients, with one patient lost to subsequent assessments. At this stage, the mean %EWL was 76% (range: 62% to 96%). No patients developed protein-energy malnutrition. However, micronutrient deficiencies were observed, with four patients (23.53%) exhibiting zinc deficiency and three (17.65%) presenting with calcium deficiency. All deficiencies were successfully managed with oral supplementation. Conclusion SADI-S effectively achieves substantial and sustained weight loss with high comorbidity resolution in individuals with high BMI. While micronutrient deficiencies require proactive management, SADI-S appears safe and yields favourable outcomes comparable to, or exceeding, those reported in larger studies. Long-term weight maintenance is promising. This study contributes valuable real-world evidence supporting the efficacy and safety of SADI-S, though larger studies are needed for further validation.

Keywords: bariatric surgery outcomes; duodenal switch; sadi-s; sleeve gastrectomy; weightloss.

Figure 1. EBWL outcomes after SADI-S at six-month, one-year and two-year follow-ups

EBWL: estimated body weight loss; SADI-S: single anastomosis duodeno-ileal bypass with sleeve gastrectomy