Gastric Bypass Superior to Medical Management of Diabetes But With Side Effects

By Marilynn Larkin

July 01, 2016

NEW YORK (Reuters Health) - Gastric bypass is more effective than lifestyle-medical management alone in achieving diabetes treatment goals, but the effect of surgery diminishes over time and is associated with more adverse events, researchers report.

Writing in Diabetes Care, online June 16, Dr. Charles Billington of the University of Minnesota Medical Center in Minneapolis and colleagues explain that they are conducting a five-year randomized study in which 60 diabetic patients receive lifestyle-medical management alone and 60 receive lifestyle-medical management plus gastric bypass. After the two-year intervention, both groups receive three years of usual medical care.

The team previously reported that after the first and second year of the study, gastric bypass was associated with improvements in rates of achieving the American Diabetes Association (ADA) composite treatment goal of HbA1c of less than 7%, low-density lipoprotein (LDL) cholesterol under 100 mg/dL, and systolic blood pressure less than 130 mmHG compared with lifestyle-medical management alone.

However, gastric bypass also was associated with an increased number of nutritional abnormalities and adverse events.

In the current study, they report on the interventions' effectiveness and risks three years after randomization -- that is, after two years of the intervention plus one year of usual medical care.

The team found that 9% of lifestyle-medical management patients and 28% of gastric bypass patients were meeting the ADA triple endpoint, which was 10% and 19% lower, respectively, than at the end of the first study year. Mean HbA1c values were 8.6% in the lifestyle-medical management group and 6.7% in the gastric bypass group.

No lifestyle-medical management patient experienced remission of diabetes, whereas 17% of gastric bypass patients had full remission and 19% had partial remission by the end of the third year. In addition, lifestyle-medical management patients used more medications (mean, 3.8) than did gastric bypass patients (1.8). The mean percent of weight loss was 6.3% for lifestyle-medical management versus 21.0% for gastric bypass.

Over the three years, 24 serious or clinically significant adverse events were observed in lifestyle-medical management patients versus 51 with gastric bypass.

Dr. Billington told Reuters Health by email, "Clinicians can be reasonably assured that gastric bypass can greatly improve blood sugar control in diabetics, although with more side effects. A minority of patients will get remission of their diabetes, and we need more study to determine how best to identify who will get that remission benefit."

"Lifestyle and intense medical management are still important after bypass and probably influence how well controlled diabetes is for the long term, even with a bypass," he concluded.

Dr. Philip Schauer, director of Cleveland Clinic's Bariatric and Metabolic Center in Ohio, told Reuters Health by email, "The study is very consistent with 11 other randomized controlled trials comparing surgical treatment with medical treatment of type 2 diabetes. It shows that gastric bypass is superior in terms of glucose control as well as other health benefits such as cardiovascular disease risk factors, hypertension, and lipidemia. And, it shows that surgical treatment is able to reduce the dependence on medications."

Dr. Schauer took issue with some aspects of the study. He noted that eight "medical" patients crossed over to the "surgery" group but their results were counted in the medical group, which made that group "look artificially better. Likewise, two patients assigned to surgery never had surgery but were counted as if they had surgery, making surgery look artificially worse."

He said that "although there were more adverse events (not statistically different) in the surgical group compared to the medical group, it seems that some of the more severe complications -- such as pancreatitis, pancreatic cancer, heart failure, suicide, depression, and one death -- may be more serious in the medical group."

In addition, he felt that some of the adverse events that occurred in the surgical arm "seem to be quite transient or unrelated to surgery-such as unwanted pregnancy, abdominoplasty, and 10 cases of transient abdominal pain."

"Lifestyle changes should always be considered first," Dr. Schauer affirmed. "When lifestyle changes and medications don't work, surgery should be considered for long-term control of blood sugar levels. After surgery, lifestyle modifications are also important."

The study was funded in part by Medtronics (Covidien). Nine coauthors report receiving funds from Medtronics and/or related companies. Dr. Schauer serves as a paid consultant for Ethicon, a surgical supply company.


Diabetes Care 2016.