Comparison of one anastomosis gastric bypass versus standard Roux-en-Y gastric bypass versus a variant of biliopancreatic diversion, in a case-matched, non-superobese population: 6 years of follow-up

Introduction
One anastomosis gastric bypass (OAGB) is gaining increasing acceptance as a simple, safe, and effective operation for treating morbid obesity. Data comparing this procedure with the most effective biliopancreatic diversions (BPD) remain scarce, and most studies evaluate OAGB against standard Roux-en-Y gastric bypass (RYGB).

Aim
To present the mid-term results of a comparison of RYGB, OAGB, and our modification of BPD in an exclusively non-superobese population, regarding safety, efficacy, preservation of weight loss, as well as late postoperative metabolic and non-metabolic complications.

Material and methods
From our cohorts of patients treated for morbid obesity with OAGB, RYGB, and BPD at Patras University Hospital, we identified patients who had case-matched preoperative profiles regarding age, preoperative body mass index (BMI), and obesity-related comorbidities (diabetes mellitus, hypertension, and dyslipidaemia). Thirty-four patients from each group were included in the study. Bariatric outcomes, non-metabolic complications, and postoperative metabolic parameters were followed until the 6th postoperative year.

Results
The average patient age was 37.4 years (range: 19–57), 85.3% were female and 14.7% were male, with a mean BMI of 46.3 kg/m2 (range: 38.3–49.7). Regarding weight loss and glycaemic control, OAGB had comparable results to BPD and was significantly better than RYGB. The safety profile was analogous to RYGB, with the exception of calcium levels, which, even though they were within normal range, were significantly lower than those in RYGB. Comorbidities were successfully treated with all operations at comparable rates. In this cohort, no other major complications were observed.

Conclusions
OAGB offered mid-term results comparable to BPD while being safe and with minimal impact on the patient’s nutritional state. It is an effective procedure for treating morbid obesity, which results in sustained weight loss and a high rate of resolution of comorbidities.