Glucose metabolism in obese patients with type 2 diabetes mellitus undergoing Standard vs. Long Limb Roux-en-Y-gastric bypass

Background Obesity surgery has been shown to be the most effective and durable treatment for type 2 diabetes mellitus (T2DM) and obesity. The optimal length of the small bowel limbs in Roux-en-Y Gastric Bypass (RYGB), the most commonly performed obesity operation in the UK, is debated and variation in practice exists. In this study, called the LONG LIMB Trial, it was hypothesised that a longer biliopancreatic limb length of 150 cm (‘Long Limb’) is superior to a standard biliopancreatic limb length of 50 cm (‘Standard Limb’) in RYGB for the treatment of T2DM. Methods This was a two-centre double-blinded randomised controlled clinical trial. Fifty participants with T2DM and obesity were randomised in 1:1 ratio to either a Long Limb or a Standard Limb RYGB. Mixed meal tolerance tests were performed to measure postprandial secretion of active GLP-1 (primary outcome) and other gut hormones, insulin, and glucose excursions and hyperinsulinaemic-euglycaemic clamps to measure insulin sensitivity pre-operatively, within 2 weeks after the surgery and at matched 20% total body weight loss (TBWL). Clinical follow up took place at 3, 6 and 12 months after the surgery. Results Within each study group, a significant increase in insulin sensitivity, insulin and active GLP-1 secretion, and reduction in glucose concentrations were observed at 2 weeks post-operatively and 20% TBWL. HbA1c and weight were significantly reduced at all post-operative clinical visits (Standard Limb: HbA1c of 73 ± 17 pre-operatively to 43 ± 10 mmol/mol at one year, p<0.001, with 30 ± 8% TBWL; Long Limb: HbA1c of 76 ± 16 to 41 ± 5 mmol/mol, p<0.001, with 29 ± 8% TBWL), However, no difference between the groups was demonstrated in any of these outcomes nor in the percentage of patients achieving T2DM (Standard Limb 62% vs. Long Limb 77%, p=0.23). Conclusion Elongation of the biliopancreatic limb of the RYGB to 150 cm does not result in superior metabolic or clinical outcomes in terms of glucose excursions, insulin and incretin hormones secretion nor insulin sensitivity, T2DM remission or weight loss within 12 months after surgery.Open Acces

Length of biliopancreatic limb in Roux-en-Y gastric bypass and its impact on post-operative outcomes in metabolic and obesity surgery-systematic review and meta-analysis

BACKGROUND: Roux-en-Y gastric bypass (RYGB) is a gold-standard procedure for treatment of obesity and associated comorbidities. No consensus on the optimal design of this operation has been achieved, with various lengths of bypassed small bowel limb lengths being used by bariatric surgeons. This aim of this systematic review and meta-analysis was to determine whether biliopancreatic limb (BPL) length in RYGB affects postoperative outcomes including superior reduction in weight, body mass index (BMI), and resolution of metabolic comorbidities associated with obesity. METHODS: A systematic search of the literature was conducted up until 1st June 2021. Meta-analysis of primary outcomes was performed utilising a random-effects model. Statistical significance was determined by p value  0.05). Even though results of four studies showed superior total body weight loss in the long BPL cohorts at 24 months post-operatively (pooled mean difference −6.92, 95% CI –12.37, −1.48, p = 0.01), this outcome was not observed at any other timepoint. CONCLUSION: Based on the outcomes of the present study, there is no definitive evidence to suggest that alteration of the BPL affects the quantity of weight loss or resolution of co-existent metabolic comorbidities associated with obesity