In patients with mild to moderate obesity and poorly controlled type 2 diabetes, adding Roux-en-Y gastric bypass surgery to intensive lifestyle and medical management more than doubles the likelihood of achieving weight-loss and metabolic goals within 1 year, according to the results of a randomized trial reported in the June 5 issue of JAMA.
However, this potential benefit must be weighed against what appears to be a moderate risk of serious adverse events, even when the procedure is done by experienced medical teams, said Dr. Sayeed Ikramuddin of the department of surgery, University of Minnesota, Minneapolis, and his associates.
In addition, the permanence of weight loss and metabolic results following the first 1-2 years after the procedure remains uncertain, as do long-term adverse events, because so few studies have adequately followed patients past that point, the investigators wrote.
Dr. Melinda A. Maggard-Gibbons
Dr. Ikramuddin and his colleagues drew these conclusions from their randomized trial of 120 patients with mild to moderate obesity (body mass index, 30.0-39.9 kg/m2) whose type 2 diabetes was poorly controlled on standard medical therapy.
In a separate report in the same issue of JAMA, Dr. Melinda Maggard-Gibbons of the University of California, Los Angeles, and her associates reported their findings from a systematic review of the literature regarding all types of bariatric surgery in similar patients with mild obesity (BMI, 30-35). They found that there still is not sufficient evidence to determine whether bariatric surgery is warranted in this patient population because of the lack of long-term data on safety and efficacy. They identified only four studies with a follow-up of more than 2 years, and those had small sample sizes or poor methodology that "preclude definitive conclusions."
Thus, neither of these investigations can support or refute the suggestion by some proponents that bariatric surgery should be extended to diabetic patients with low-grade obesity to improve their glycemic control.
In their prospective, unblinded clinical trial, Dr. Ikramuddin and his associates offered a free, intensive lifestyle and medical-therapy weight control program to the 120 study subjects at one academic medical center in Minnesota, one in New York, and two in Taiwan over a 3-year period. All patients were between 30 and 67 years of age and had hemoglobin A1c (HbA1c) levels of 8% or higher (mean, 9.6%); the average duration of diabetes was 9 years.
The program included daily weigh-ins and detailed diaries of eating and exercise, with caloric intake goals of 1,200-1,800 kcal/day and moderate physical activity for at least 325 min/week to achieve a weight loss of 1-2 pounds/week. The study subjects met regularly with trained interventionists to discuss weight management and to enhance adherence.
Patients could add orlistat or, until it was withdrawn from the market, sibutramine for weight control. Medications for glycemic control were added as necessary, as were aspirin therapy and medications to control cholesterol levels and blood pressure.
Half of the study subjects were then randomly assigned to undergo laparoscopic Roux-en-Y gastric bypass. This group was given multivitamin and mineral supplements.
The endpoint of the study was a triple outcome endorsed by the American Diabetes Association: an HbA1c level of less than 7%, a low-density lipoprotein (LDL) cholesterol level of less than 100 mg/dL, and a systolic blood pressure of less than 130 mm Hg at 1-year follow-up.
A total of 28 patients (49%) in the gastric bypass group achieved this end point, compared with only 11 (19%) in the lifestyle/medical management group, Dr. Ikramuddin and his colleagues reported (JAMA 2013;309:2240-49).
Of these three components of the combined endpoint, only HbA1c level showed a significant difference between the two study groups: 43 (75%) of the surgery group achieved an HbA1c level under 7%, compared with just 18 (32%) of the lifestyle/medical management group.
The difference in outcomes between the two groups was attributed chiefly to their difference in weight loss. The mean loss at 1 year was 26% of baseline weight after gastric bypass, compared with 8% with the intensive lifestyle/medication program.
Patients in the surgery group continued to lose weight throughout the year of follow-up, while those in the other group tended to lose weight during the first 6 months and plateau after that.
On average, at 1 year the patients in the surgery group required three fewer medications than did those in the other group to manage glycemia, dyslipidemia, and hypertension.
However, patients who underwent gastric bypass had 50% more serious adverse events and 55% more nonserious adverse events than did those who did not. "All surgeons performing gastric bypass in this study were experts; thus the occurrence of serious complications must be factored into the design of larger trials of effectiveness for patients with moderate obesity," Dr. Ikramuddin and his associates said.