Single anastomosis duodeno-ileal bypass with sleeve gastrectomy versus Roux-en-Y gastric bypass: A multicenter randomized controlled Trial after Experiencing suboptimal initial response Post-Sleeve gastrectomy (STEPS)

Background and rationale:

Obesity is a major global health concern associated with increased morbidity and mortality due to type 2 diabetes, cardiovascular disease, and other comorbidities. Laparoscopic sleeve gastrectomy (SG) has become the most frequently performed bariatric procedure worldwide and generally achieves substantial weight reduction and metabolic improvement. However, up to 36% of patients experience weight regain or insufficient weight loss, necessitating revisional surgery. The Roux-en-Y gastric bypass (RYGB) remains the standard conversion procedure, while the single-anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S) has emerged as a promising alternative that may enhance metabolic benefits and weight outcomes. Despite the increasing use of SADI-S, there is a significant knowledge gap regarding its comparative effectiveness and safety versus RYGB in patients with prior SG 

Aim(s):

Within the STEPS-Trial, we will investigate whether, among patients with a suboptimal response to SG, conversion to SADI-S leads to greater total weight loss one year after surgery compared to the current standard of care, RYGB. 

Study design and methodology:

This is a multicenter, randomized, controlled, open-label, superiority trial. A total of 190 adult patients who have undergone SG and present with either <20% total weight loss or >30% weight regain from the lowest post-surgery weight will be randomized 1:1 to undergo either SADI-S or RYGB with standardized limb lengths (SADI-S: 300 cm common channel; RYGB: 300 cm common channel and 100 cm alimentary limb). Patients with gastroesophageal reflux disease (GERD-Q ≥8 or LA grade ≥C) will be excluded. Follow-up will occur at 3, 6, and 9 months, and annually up to 5 years. 

The primary endpoint is total weight loss (%TWL) at one year post-surgery. Secondary endpoints include excess BMI loss (%EBMIL), incidence of nutritional deficiencies, quality of life, safety parameters, and long-term complication rates. We calculated a target sample size of 190 patients to have a power of 90% using a two-sided α of 0.05. 

Expected impact:

The STEPS Trial will be the first RCT designed exclusively to directly compare SADI-S and RYGB as required conversion procedures following SG. It will generate further high-quality evidence on their relative efficacy and safety, guiding clinical decision-making and improving long-term care for patients with suboptimal outcomes after primary SG.