Medical therapies such as low-calorie diets, exercise, and pharmacotherapy have been only modestly effective in achieving clinically significant weight loss in obese adults. There is good evidence that bariatric surgery produces sustained weight loss and improved quality of life in morbidly obese adults (body mass index [BMI] greater than 35 kg per m2). It is uncertain whether surgery offers additional benefits for patients who are mildly to moderately obese (BMI 30 to 35 kg per m2). O’Brien and colleagues conducted a randomized controlled trial that compared the effectiveness of laparoscopic adjustable gastric banding to an intensive medical program for weight loss, health status, and quality of life after 24 months of treatment.
The study was conducted in Australia and consisted of 80 adults with a BMI of 30 to 35 kg per m2 who were recruited through a newspaper advertisement. All participants had at least one obesity-related medical condition, physical limitation, or clinically significant psychosocial problem, and all had previously attempted to lose weight. Patients with a history of bariatric surgery, previous participation in an intensive medical weight loss program, or contraindications for treatment in either study group were excluded. At two initial educational sessions, all participants were given information about health problems associated with obesity and encouraged to exercise for at least 200 minutes per week.
Participants were then randomly assigned to a surgical or nonsurgical program. Those in the surgical program underwent placement of a laparoscopic adjustable gastric band at a private community hospital within one month. Two surgeons with expertise in the procedure conducted all of the surgeries and reviewed patient progress every four to six weeks. If clinically indicated, the volume of the gastric band was adjusted by adding saline to a subcutaneous access port. Patients in the nonsurgical program followed a very-low-calorie diet (500 to 550 kcal per day) for six months and were subsequently monitored by study physicians at least every six weeks to reinforce healthy dietary and exercise behaviors. Pharmacotherapy included orlistat (Xenical) but not sibutramine (Meridia), which was not available in Australia when the study began. At follow-up, 39 of 40 participants in the surgical group and 33 of 40 in the nonsurgical group had completed the study protocol. All participants were included in the intention-to-treat analysis.
The primary outcome measure was weight change at 24 months. Both groups lost 13.8 percent of initial weight after six months. After 24 months, the surgical group had lost an average of 21.6 percent of initial weight, whereas the nonsurgical group steadily re-gained to complete the study with an average of 5.5 percent of initial weight lost. Secondary outcomes included health status and quality of life. The surgical group experienced greater improvements than the nonsurgical group in blood pressure, fasting plasma glucose levels, insulin sensitivity, and high-density lipoprotein cholesterol measurements. Fourteen of the 15 participants in the surgical group who had met Adult Treatment Panel III criteria for metabolic syndrome at the beginning of the study no longer met these criteria at 24 months. The surgical group also reported greater improvements in quality of life as measured by a standardized questionnaire than did the nonsurgical group.
The authors conclude that laparoscopic adjustable gastric banding led to greater improvements in weight loss, health status, and quality of life in mild to moderately obese adults than an intensive medical therapy program. Although few adverse events occurred in either group, this study was not powered to compare the safety of the programs. In light of these results, the authors suggest revisions to guidelines that restrict eligibility for bariatric surgical procedures to adults with BMIs greater than 35 kg per m2.