Metabolic and Bariatric Surgery

What the evidence says

Sleeve gastrectomy and Roux-en-Y gastric bypass are distinct operations, not interchangeable versions of one intervention. Modern guidelines broaden eligibility beyond older BMI-only thresholds, but selection still requires multidisciplinary assessment and a plan for lifelong nutritional and medical follow-up.^[1]

In STAMPEDE, adults with type 2 diabetes and BMI 27 to 43 had mean five-year weight changes of about -23% after bypass, -19% after sleeve, and -5% with intensive medical therapy. Glycemic control and medication use also favored surgery.^[2]

Ten-year randomized follow-up confirms substantial durability. SLEEVEPASS and SM-BOSS found large persistent loss after both procedures, while bypass generally produced somewhat greater loss and sleeve caused more new reflux and more conversion surgery. A broader long-term review likewise found durable benefit with procedure-specific differences.^[3][4][7]

A one-stage meta-analysis of 174,772 participants associated bariatric surgery with a 49% lower mortality hazard and about 6.1 additional median life-years versus usual care. Nearly all survival evidence was non-randomized, so healthier-patient selection and other residual confounding may inflate the estimate.^[5]

Contemporary pooled perioperative mortality is low at roughly 0.08%, but not zero. Leaks, bleeding, reflux, dumping, gallstones, nutritional deficiencies, bone effects, alcohol-related risk, and later reoperation vary by procedure and require long-term monitoring.^[6][1]