Bariatric Surgery: Crossing a Body Mass Index Threshold

As many as 5% of adults in developed nations now have extreme obesity, characterized by a body mass index (BMI) of 40 kg/m² or more (1). These individuals have a mortality rate that is at least double that of individuals with a BMI in the desirable range of 18.5 kg/m² to 24.9 kg/m²(2). More than 40 years of research has shown that surgical intervention, particularly the gastric bypass, is the treatment of choice for extremely obese individuals who cannot control their weight with traditional methods, such as lifestyle modification or pharmacotherapy (3, 4). Bariatric surgery also is indicated for individuals with BMIs of 35.0 kg/m² to 39.9 kg/m² who have comorbid conditions, including type 2 diabetes, hyperlipidemia, and sleep apnea (5, 6). Both the gastric bypass and the newer laparoscopic adjustable gastric banding improve these conditions (3, 4). The gastric bypass is generally considered to be the more effective of the 2 procedures, but it is associated with higher mortality than laparoscopic adjustable gastric banding (4).

The report by O'Brien and colleagues (7) in this issue provides the strongest evidence to date of the benefits of bariatric surgery relative to lifestyle modification and pharmacotherapy. The authors successfully completed a 2-year randomized, controlled trial in which 80 obese adults (BMI, 30.0 kg/m² to 34.9 kg/m²) were assigned to laparoscopic adjustable gastric banding or treatment by a very-low-calorie diet combined with the weight loss medication orlistat. Patients in both groups lost 13.8% of initial weight during the first 6 months. The 2-year assessment, however, revealed the clear superiority of laparoscopic adjustable gastric banding. Surgically treated patients continued to lose weight, reaching a 21.8% reduction at the second year. By contrast, participants in the nonsurgical group regained weight steadily …