OAGB vs RYGB: No difference in weight loss, metabolic effects
One anastomosis gastric bypass (OAGB) is as effective as the standard Roux-en-Y (RYGB) procedure in terms of weight loss and metabolic improvements 24 months after the surgery, according to the results of the open-label YOMEGA* trial.
“The good weight loss and metabolic outcomes of OAGB could be explained by the malabsorptive effect of the procedure,” which is supported by higher incidences of diarrhoea, steatorrhoea and nutritional complications in the OAGB vs the RYGB group, said principal study investigator Prof Maud Robert from the The Université Hospital of Lyon in France.
YOMEGA enrolled 253 individuals aged 18–65 years with body mass index (BMI) of ≥40 kg/m2 or ≥35 kg/m2 with the presence of at least one comorbidity. Only 234 (mean age, 43.5 years; 75 percent female; mean BMI, 43.9 kg/m2; 27 percent had type 2 diabetes) were included in the analysis—the first half underwent OAGB and the other RYGB.
At 2 years postsurgery, the primary endpoint of reduction in excess BMI was similar in the OAGB and RYGB groups (mean, –87.9 percent vs –85.8 percent, respectively), confirming noninferiority of a single gastrojejunal anastomosis (mean difference, –3.3 percent; 95 percent CI, –9.1 to 2.6). [Lancet 2019; 393:1299-1309]
Mean HbA1C at 2 years also did not significantly differ between the two groups (5.2 percent vs 5.5 percent; p=0·066), although the documented HbA1C reduction was notably greater in the OAGB group (–1.2 percent vs –0.6 percent; p=0.0037). Likewise, there was no significant difference in the number of participants with diabetes who went into remission (14 of 20 vs 7 of 16; p=0.28).
Almost twice as many serious adverse events occurred with OAGB (overall, 67 vs 38; p=0.009; associated with surgery, 42 vs 24; p=0.042). Among the surgery-related serious adverse events, nine (21 percent) were nutritional complications in the OAGB group vs none in the RYGB group (p=0.0034). Participants with nutritional complications had at least one vitamin deficiency, malnutrition, anaemia or iron deficiency, or a combination of these.
Diarrhoea also occurred more frequently in the OAGB group at 3 months (26 percent vs 3.2 percent; p=0.0003; odds ratio [OR], 11.53; 3.03–43.86) and at 2 years postsurgery (19.7 percent vs 7 percent; p=0.04; OR, 3.07, 1.04–9.08). This was also true for the incidence of steatorrhoea, which was significantly higher than in the RYGB group at 6 months (11 vs 7 g of lipids per 100 g stools; p=0.0002).
The mean operative time was significantly shorter in the OAGB vs RYGB group (85 vs 111 min; p<0.0001), but the median duration of hospital stay was 5 days for both groups. RYGB consisted of a 150-cm alimentary limb and a 50-cm biliary limb, whereas OAGB involved a single gastrojejunal anastomosis with a 200-cm biliopancreatic limb.
Despite the presence of limitations such as the restricted number of patients, relatively short follow-up and low follow-up rate, “[t]he entirety of evidence and the results of the present study support the efficacy of OAGB in terms of weight loss and metabolic improvement as compared with the validated RYGB and is in favour of a malabsorptive effect of the OAGB,” Robert said.
In an accompanying editorial, Drs Sten Madsbad and Jens Holst from the University of Copenhagen in Denmark noted that YOMEGA raises awareness regarding nutritional and inflammatory complications associated with OAGB, which otherwise appears to have similar metabolic effects to RYGB. [Lancet 2019;393:1263-1364]
“In other words, even if the weight loss and antidiabetic actions of a new procedure are attractive, no guarantee exists that its long-term safety profile is the same. Thus, strict follow-up after bariatric surgery is important after new procedures, as well as old procedures,” they wrote.
*Omega Loop Versus Roux-en-Y Gastric Bypass