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Key Points

  • image Sixty-five percent of the world’s population live in countries where overweight and obesity are linked to more deaths than underweight and malnutrition. Obesity is the second leading cause of preventable death in adults in the United States.

  • image There is an ongoing major shift in procedure utilization with the sleeve gastrectomy and Roux-en-Y gastric bypass being the two most common procedures, worldwide.

  • image The former classification of bariatric operations as either “restrictive” or “malabsorptive” is being replaced by knowledge from investigation into the more basic physiologic and metabolic mechanisms responsible for the effects of bariatric surgery.

  • image Patients who develop a bowel obstruction after laparoscopic gastric bypass require surgical and not conservative therapy due to the high incidence of internal hernias and the potential for bowel infarction.

  • image Malabsorptive operations are highly effective in producing durable weight loss and metabolic improvements but have higher surgical complication rates and considerable nutritional side effects. Patients undergoing such procedures require complete follow-up and appropriate nutritional supplements.

  • image Large, longer-term observational studies of bariatric surgery have shown durable weight loss, diabetes remission, lipid improvements, and improved survival with bariatric surgery. Still unclear are specific pre- and postoperative predictors of those outcomes, long-term complications, microvascular and macrovascular events, mental health outcomes, and costs.

  • image High quality data have clearly established that bariatric procedures are more effective than medical or lifestyle interventions for inducing weight loss and initial remission of type 2 diabetes, even in less obese patients. Randomized clinical trials showed greater weight loss and type 2 diabetes mellitus remission following bariatric surgery compared with nonsurgical treatments.

  • image The incidence of complications after bariatric surgery varies from 4% to over 25% and depends on the duration of follow-up, the definition of complication used, the type of bariatric procedure performed, and individual patient characteristics.

  • image Emerging areas in bariatric surgery include the use of intermediate weight loss devices, adolescent bariatric surgery, and the increase in the need for revision and conversion bariatric procedures.


Despite the global pandemic of obesity, there has been little progress in nonsurgical treatment approaches, especially among patients with severe obesity. In addition, the evidence base for bariatric procedures has grown rapidly over the last 10 years, yielding important short- and long-term data on the safety and efficacy of the surgical treatment for obesity and related metabolic disorders. Therefore, the approach for patients considering bariatric and metabolic surgery has now shifted to a well-informed and shared decision-making process as there are significant tradeoffs between the potential risks and benefits of these procedures.1


During the 1950s, operations were first performed to treat severe hyperlipidemia with associated obesity.2 These were ileocolic bypass operations to limit absorption and were associated with severe nutritional complications and liver failure postoperatively. A more modest jejunoileal bypass was performed next, also a malabsorptive operation, but it bypassed only a portion of the small intestine. Complications after ...

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