Ring-augmented gastric bypass shows similar weight loss and safety at one year

This randomized controlled trial (RCT) conducted at a single center compared ring-augmented one-anastomosis gastric bypass (OAGB) with conventional OAGB in 214 adult patients eligible for primary OAGB. The study aimed to evaluate short-term outcomes including perioperative safety, adverse events, and weight outcomes at one year. The primary outcome was not explicitly stated, but the analysis focused on these endpoints.

Both groups had a mean operation time of 51 minutes (standard deviation 13 minutes), with no statistically significant difference (p=0.84). Perioperative complication rates were identical: one patient in each group (0.9%) experienced a complication (p=1.00). Postoperative minor complications (Clavien-Dindo grade 1-2) and major complications (grade 3-5) also showed no significant differences (p=0.68 and p=0.77, respectively).

Weight outcomes at one year were comparable between groups. Mean body mass index (BMI) was 28 kg/m2 in both groups. Percent total weight loss (%TWL) was 33% in the ring-augmented group versus 31% in the conventional group (p=0.30). Percent excess weight loss (%EWL) was 86% versus 84% (p=0.45). Neither difference reached statistical significance.

Safety findings were similar. Two Minimizer rings were electively removed at patients' request during the first year, without observed complications related to the ring. No serious adverse events were reported, and tolerability data were not provided.

Compared to prior landmark studies of OAGB, the weight loss results are consistent with expected outcomes for this procedure. However, the addition of a ring did not confer a statistically significant advantage in weight loss at one year. The study is limited by its single-center design and relatively short follow-up of 12 months. Longer-term outcomes are needed to assess durability of weight loss and potential late complications.

Key methodological limitations include the lack of a clearly stated primary outcome, which raises concerns about multiplicity and selective reporting. The study is not powered to detect rare adverse events, and the absence of blinding may introduce bias. Additionally, the generalizability may be limited as all procedures were performed at a single center.

For clinical practice, these results suggest that ring augmentation of OAGB does not improve short-term weight loss or safety compared to conventional OAGB. However, the absence of a statistically significant difference does not prove equivalence. Clinicians should consider that the ring may be removed in some patients, and longer-term data are required before recommending routine use.

Unanswered questions include whether ring augmentation provides any benefit in preventing weight regain or reducing reflux, and whether certain patient subgroups might derive greater benefit. Longer follow-up from this trial and additional studies are needed to clarify the role of ring augmentation in OAGB.