RYGB more efficient than SG and more evidence is needed for OAGB

Updated: Feb 14

Roux-en-Y gastric bypass (RYGB) is more efficient (excess weight loss, EWL percentage) than sleeve gastrectomy (SG) after five years, according to the outcomes of a systematic review and meta-analysis of 25 randomised-controlled trials (RCTs). The findings - by researchers from the University Hospitals of Geneva, Genève, Switzerland, were featured in the paper, ‘Roux-en-Y gastric bypass, sleeve gastrectomy, or one-anastomosis gastric bypass? A systematic review and meta-analysis of randomized-controlled trials’, published in in the journal Obesity – also reported that one-anastomosis gastric bypass (OAGB) also resulted in greater EWL than RYGB after one year, although further evidence is needed to confirm this result.

Following a literature search, 25 RCTs were included in the analysis with a total of 2,715 patients. Trials comparing RYGB vs SG included 14 from Europe, three from Asia, two from the US and one in Brazil. Eleven studies had weight loss as primary outcome and eight studies as weight loss as a secondary-outcomes. For RYGB and OAGB trials, three were in Europe, one in Taiwan and Venezuela, respectively.


Total weight loss (TWL percentage) between RYGB and SG was similar between both procedures at one month, but RYGB showed a better TWL (percentage) at three and six months, one and five years. Out of the five RCTs comparing RYGB and OAGB, none reported TWL (percentage). Excess weight loss (EWL percentage) between RYGB and SG was similar between at one month and all subsequent reporting times out to two years. At three and five years, EWL was greater in RYGB patients vs SG patients. In a comparison of RYGB and OAGB, there was a greater EWL for OAGB at one year.

Excess BMI loss (percentage) between RYGB and SG was similar at time periods out to five years. Outcomes between RYGB and OAGB was only reported in the YOMEGA trial. At two years, the OAGB group showed an EBMIL (percentage) of 87.9% (23.6%) vs RYGB of 85.8% (23.1%)

Regarding remission of T2DM between the procedures, 14 RCTs compared RYGB with SG (seven trials were issued from the same group of patients), with all studies defined complete diabetes remission as a haemoglobin A1c level of <6% and/or fasting blood glucose of <100mg/dL. The outcomes showed that there was no difference in terms of remission of type 2 diabetes from one month out to five years.

Only two RCTs reported T2DM remission rates after RYGB and OAGB, although similar rates of remission were reported, no sufficient meta-analysis could be performed due to the low numbers and limited time points included in the studies.

The authors noted that in addition to weight loss and T2DM remission, incidences of GERD, malnutrition, diarrhoea, bowel obstruction and internal hernia warrant further investigation.

“RYGB is more efficient than SG in terms of TWL (percentage) and in terms of EWL (percentage), notably in the midterm,” the authors concluded. “However, no advantage emerged regarding type 2 diabetes remission. OAGB seems to be a procedure offering greater EWL (percentage) than RYGB after one year, but further evidence is needed to confirm this result.”

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