Bariatric surgery--from treatment of disease to prevention?

Bariatric surgery to treat morbid obesity has improved dramatically over the past 60 years — especially over the past several decades. Today’s methods are far safer than the hazardous intestinal bypass procedures that were introduced in the 1950s. Bariatric-surgery techniques have progressed through various iterations of horizontal and vertical stapling of the stomach with or without banding (e.g., vertical banded gastroplasty) to vertical gastric partitioning or creation of a gastric pouch with proximal bypass into a jejunal loop (i.e., the gastric bypass), which is considered to be a reference standard. Currently, inflatable bands that can be placed laparoscopically are an accepted method by which to restrict the size of a patient’s stomach and restrict oral intake. Partial gastric resection with distal diversion of biliopancreatic secretions relative to the orally ingested nutrients (e.g., the biliopancreatic diversion procedure) has also been proved to be efficacious. There is now good evidence that operations such as Roux-en-Y gastric bypass, laparoscopic gastric banding, and biliopancreatic diversion are associated with low mortality and with rates of complications that are similar to those with other major surgical procedures.1 In each instance, the original goals of these operative procedures were to facilitate weight loss and, thereby, to improve the health of the patients. Bariatric surgery was recommended for patients who did not lose an adequate amount of weight with lifestyle changes or pharmacotherapy and who met the National Institutes of Health (NIH) consensus criteria for candidacy, which was a body-mass index (BMI, the weight in kilograms divided by the square of the height in meters) of at least 40.2,3 Patients who had a BMI of at least 35 and serious coexisting medical conditions could also be considered for bariatric surgery. These criteria were established in recognition of the relationship between obesity and the risk of coronary artery disease, type 2 diabetes, and sleep apnea, among other risks. In the two decades since the publication of these NIH consensus criteria, the results from an ever-increasing number of clinical trials indicate that bariatric surgery can result in durable weight loss in many patients and may also ameliorate obesity-associated coexisting conditions. These observations, and especially the finding of a dramatic effect of bariatric surgery on glycemic control in patients with type 2 diabetes — such that the need for medical therapy was decreased or eliminated in many patients — has garnered significant attention. For example, Sjöström and colleagues, in the Swedish Obese Subjects (SOS) study, provided evidence that many patients who underwent bariatric surgery could have prolonged improvement in blood-sugar control in addition to a lower risk of cardiovascular complications.4 Two randomized, controlled trials published in the Journal in 2012 provided additional strong evidence that bariatric surgery could be more effective than either standard or intensive medical treatment.5,6 The findings of these studies led to speculation about whether surgery might be considered earlier in the course of disease in patients with adult-onset diabetes.7 In this issue of the Journal, Carlsson and colleagues describe the long-term effects of bariatric surgery on the prevention of type 2 diabetes in obese patients.8 In this nonrandomized, but casematched, prospective study, which was initiated An interactive illustration of four current bariatric surgical procedures is available at NEJM.org