Outcomes of One-Anastomosis Gastric Bypass Conversion to Roux-en-Y Gastric Bypass for Severe Obesity: A Systematic Review and Meta-analysis.

One-anastomosis gastric bypass (OAGB) is an effective procedure to treat severe obesity. However, conversion to Roux-en-Y gastric bypass (RYGB) is increasing. We therefore conducted a systematic review to determine the safety and efficacy associated with OAGB-RYGB conversion. A systematic search was conducted by three independent reviewers using Medline, Embase, and the Cochrane library following PRISMA guidelines. Six studies including 134 patients were selected who were undergoing OAGB-RYGB conversion. The most common indications were reflux (47.8%), malnutrition (31.3%), and inadequate weight loss (8.2%). Study outcomes demonstrated 100% resolution of bile reflux. Overall, there was medium-term weight gain of 0.61 BMI. OAGB to RYGB conversion leads to resolution of reflux symptoms. However, it is associated with weight regain, albeit this may be acceptable to patients to treat biliary reflux.