Gastric bypass surgery may help manage diabetes risk factors
Among mild to moderately obese patients with type 2 diabetes, adding gastric bypass surgery to lifestyle and medical management was associated with a greater likelihood of improved levels of metabolic risk factors such as blood glucose, LDL-cholesterol and systolic blood pressure, according to a study in the June 5 issue of JAMA.
"The foundation of treatment for type 2 diabetes mellitus is weight loss, achieved through reduction of energy intake and increased physical activity via lifestyle modification. Results from the Look AHEAD (Action for Health in Diabetes) trial show that sustained weight loss through lifestyle modification improves diabetes control, but this is difficult to achieve and maintain over time," according to background information in the article. "Controlling glycemia, blood pressure, and cholesterol is important for patients with diabetes. How best to achieve this goal is unknown."
Sayeed Ikramuddin, M.D., of the University of Minnesota, Minneapolis, and colleagues conducted a study to compare Roux-en-Y gastric bypass with lifestyle and intensive medical management to achieve control of comorbid (co-existing) risk factors. The 12-month, 2-group randomized trial was conducted at 4 teaching hospitals in the United States and Taiwan and included 120 participants who had a hemoglobin A1c (HbA1c) level of 8.0 percent or higher, body mass index (BMI) between 30.0 and 39.9, C peptide level of more than 1.0 ng/mL, and type 2 diabetes for at least 6 months. The study began in April 2008. The interventions for the trial were lifestyle-intensive medical management intervention and Roux-en-Y gastric bypass surgery. Medications for hyperglycemia, hypertension, and dyslipidemia were prescribed according to protocol and surgical techniques that were standardized.
The composite goal for the study was the goal established by the American Diabetes Association (ADA) for the treatment of diabetes: HbA1c less than 7.0 percent, low-density lipoprotein cholesterol less than 100 mg/dL, and systolic blood pressure less than 130 mm Hg.
All 120 patients received the Look AHEAD intensive lifestyle-medical management protocol, the protocol used in the Look AHEAD study and considered to be the most successful for treating diabetes in obese patients; 60 of the 120 patients were randomly assigned to undergo Roux-en-Y gastric bypass. The researchers found that at 12 months, 11 participants (19 percent) in the lifestyle-medical management group and 28 (49 percent) in the gastric bypass group achieved the primary composite end point. Among the composite end point components, the only significant treatment effect was for HbA1c: 18 participants (32 percent) in the lifestyle-medical management group vs. 43 (75 percent) in the gastric bypass group achieved an HbAlc level of less than 7 percent.
The lifestyle-medical management group lost an average of 7.9 percent of initial body weight at 1 year, whereas the average weight loss in the gastric bypass group was 26.1 percent. "On average, the gastric bypass group used 3.0 fewer medications to manage glycemia, dyslipidemia, and hypertension than did those in the lifestyle-medical management group. The gastric bypass group also had significantly better results for the secondary outcomes of glycemia, HDL cholesterol, triglycerides, and diastolic blood pressure," the authors write.
Analyses indicated that achieving the composite end point was primarily attributable to weight loss. The gastric bypass group experienced more nutritional deficiency than the lifestyle-medical management group. Overall, there were 22 serious adverse events in the gastric bypass group and 15 in the lifestyle-medical management group.
This study overcame limitations of prior studies of bariatric surgery by using a widely accepted nonsurgical treatment protocol, used endpoints recommended as the major goal for treatment by the ADA, was performed by multiple surgeons of different hospitals and studied a single operative procedure, the Roux-en-Y gastric bypass, considered to be the best procedure for weight loss.
"The merit of gastric bypass treatment of moderately obese patients with type 2 diabetes depends on whether potential benefits make risks acceptable. Bariatric surgery can result in dramatic improvements in weight loss and diabetes control in moderately obese patients with type 2 diabetes who are not successful with lifestyle changes or medical management. The benefits of applying bariatric surgery must be weighed against the risk of serious adverse events," the researchers conclude.
In an accompanying editorial, Bruce M. Wolfe, M.D., of Oregon Health and Science University, Portland, and colleagues comment on the two articles in this issue of JAMA regarding weight loss surgery and diabetes.
"Recent large scale trials of intensive medical management for obesity and diabetes have been disappointing. Substantial resources are required to cause modest weight loss and diabetes control. Bariatric surgery does result in substantial weight loss with excellent diabetes control but is offset by initial high cost and risks for surgical complications. The optimal approach for treatment of obesity and diabetes remains unknown. The answer will only come from more well designed, randomized trials such as that performed by Ikramuddin et al that provide definitive answers."