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

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.

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.

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.

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.