Efficacy and effects of bariatric surgery in the treatment of obesity: Network meta-analysis of randomized controlled trials

Aims: Bariatric surgery (BS) is recommended for subjects with a Body Mass Index (BMI) over of 40 kg/m2 or with a BMI between 35 and 40 kg/m2 with obesity-related comorbidities. Aim of the study was to compare different types of BS with medical therapy (MT) for the treatment of obesity. Data synthesis: We conducted a network-meta-analysis (NMA) including randomized clinical trials comparing different BS techniques versus MT in people with obesity, with a duration ≥24 weeks (PROSPERO, #CRD42020160359). Primary endpoint was BMI. Indirect comparisons of different types of surgery were performed by NMA. Types of BS included: laparoscopic adjustable gastric banding (LAGB), Roux-en-Y gastric bypass, sleeve gastrectomy (SG), bilio-pancreatic diversion (BPD); greater curvature plication (GCP); one-anastomosis gastric bypass (OAGB); Laparoscopic Vertical Banded Gastroplasty (LVBG) and duodenal switch (DS). 43 trials were retrieved in this metanalysis. BS was associated with a significant reduction in BMI, systolic blood pressure, triglyceride and fasting glucose, and with a significant increase of HDL cholesterol when compared to MT. In direct comparisons, RYGB was more effective than LAGB, LVBG, and GCP, but less effective than DS, whereas LAGB was less effective than LVBG and SG. In the NMA, DS and BPD appeared to be more effective than other procedures. Conclusions: BS produces a greater weight loss than MT in morbidly obese patients, inducing a greater improvement of obesity-associated metabolic parameters. Available data are insufficient to assess the effect of BS on mortality. Different surgical procedures are heterogeneous for efficacy and safety.