Importance: Severe obesity and its related diseases, such as type 2 diabetes, hypertension, dyslipidemia, and sleep apnea, are very common in the United States, but currently very few patients with these conditions choose to undergo bariatric surgery. Summaries of the expanding evidence for both the benefits and risks of bariatric surgery are needed to better guide shared decision-making conversations.
Observations: There are approximately 252 000 bariatric procedures (per 2018 numbers) performed each year in the US, of which an estimated 15% are revisions. The 1991 National Institutes of Health guidelines recommended consideration of bariatric surgery in patients with a body mass index (calculated as weight in kilograms divided by height in meters squared) of 40 or higher or 35 or higher with serious obesity-related comorbidities. These guidelines are still widely used; however, there is increasing evidence that bariatric procedures should also be considered for patients with type 2 diabetes and a body mass index of 30 to 35 if hyperglycemia is inadequately controlled despite optimal medical treatment for type 2 diabetes. Substantial evidence indicates that surgery results in greater improvements in weight loss and type 2 diabetes outcomes, compared with nonsurgical interventions, regardless of the type of procedures used. The 2 most common procedures used currently, the sleeve gastrectomy and gastric bypass, have similar effects on weight loss and diabetes outcomes and similar safety through at least 5-year follow-up. However, emerging evidence suggests that the sleeve procedure is associated with fewer reoperations, and the bypass procedure may lead to more durable weight loss and glycemic control. Although safety is a concern, current data indicate that the perioperative mortality rates range from 0.03% to 0.2%, which has substantially improved since early 2000s. More long-term randomized studies are needed to assess the effect of bariatric procedures on cardiovascular disease, cancer, and other health outcomes and to evaluate emerging newer procedures.
Conclusions and relevance: Modern bariatric procedures have strong evidence of efficacy and safety. All patients with severe obesity-and especially those with type 2 diabetes-should be engaged in a shared decision-making conversation about the risks and benefits of surgery compared with continuing usual medical and lifestyle treatment, and the decision about surgery should be driven primarily by informed patient preferences.