Weight loss outcomes for patients undergoing conversion to Roux-en-Y-gastric bypass after sleeve gastrectomy

Background: Despite excellent reported outcomes after laparoscopic sleeve gastrectomy (LSG), a percentage of patients go on to have a secondary bariatric surgery to manage side-effects or address weight regain after LSG. Reported weight loss outcomes for patients undergoing laparoscopic Roux-en-Y gastric bypass (LRYGB) after previous LSG are variable. We sought to determine the weight-loss outcomes of patients undergoing LRYGB after LSG in the largest bariatric surgical network in Canada and to determine whether outcomes differ according to indications for conversion.

Methods: The Bariatric Registry is a multi-center database with prospectively collected standardized data on patients undergoing bariatric surgery at ten Bariatric Centers of Excellence within the Ontario Bariatric Network in Ontario, Canada. A retrospective analysis was performed of patients who underwent LRYGB after previous LSG between 2012 and 2019. Weight loss outcomes were compared between patients who underwent LRYGB for insufficient weight loss/weight regain and those who underwent conversion to LRYGB for other reasons.

Results: Excluding patients with multiple revisions and those without follow-up data, 48 patients were included in the analysis: 33 patients (69%) underwent conversion to LRGYB for insufficient weight loss/weight regain (Group 1) and 15 patients (31%) underwent conversion for other reasons (Group 2). Mean body mass index (BMI) measured pre-LSG, pre-LRYGB, and at mid-term follow-up after LRYGB was 61, 48, and 43 kg/m² in Group 1 and 51, 39, and 34 kg/m² in Group 2, respectively. ΔBMI and %total weight loss (TWL) at mid-term follow-up were not significantly different between the groups.

Conclusions: Conversion to LRYGB after previous LSG resulted in an additional loss of 4 kg/m² in BMI points at mid-term follow-up. Patients lost a similar number of BMI points and cumulative %TWL was similar regardless of reason for conversion. This can help inform surgical decision-making in the setting of weight regain after LSG.