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Studies to assess surgery for T2DM patients with BMI>26

New study is open to patients with a BMI>26
Study to determine the endocrine effects specific to gastric bypass surgery beyond those associated with non-surgical weight loss
Pilot study to assess patients undergoing ileal transposition with sleeve gastrectomy

A recently announced clinical trial will assess whether surgery can control type 2 diabetes as well or even better than the best medical treatment available. It is believed that this is the first study of its kind open to patients who are overweight or mildly obese.


United States guidelines currently state that bariatric surgery is only indicated for the treatment of severe or morbid obesity, defined as having a body mass index (BMI) of 35 or greater. This new study is open to patients with a BMI as low as 26. Patients with a BMI <26 and >35 will not be considered for enrollment in the trial.


Previous research has shown that in severely obese patients (BMI >35) gastric bypass surgery is a safe and effective way to treat type 2 diabetes. It has been shown to improve blood glucose levels, reduce or even eliminate the need for medication, and lower the risk for diabetes-related death.


Francesco Rubino

"There is preliminary evidence suggesting that that these results are attainable even in overweight or mildly-obese patients," says Dr Francesco Rubino, Chief of the Gastrointestinal Metabolic Surgery Program at NewYork-Presbyterian Hospital/Weill Cornell Medical Center and Associate Professor of Surgery at Weill Cornell Medical College.


In support of this belief, recommendations from the American Diabetes Association's January 2009 issue of Standards of Care: Diabetes Care, and from the Diabetes Surgery Summit Consensus Conference, published in the March 2010 issue of Annals of Surgery, suggest that randomised clinical trials for the study of surgery in patients with BMI below 35 are priority for diabetes research.


"Having a potentially effective surgical option against diabetes does not mean that surgery is the best choice for every diabetic patient," added Rubino. "We need rigorous, comparative clinical trials, like this one, in order to better understand when to prioritize surgery and when to recommend traditional medical treatment."


Clinical study

The new study is enrolling 50 patients with type 2 diabetes who will be randomized to receive Roux-en-Y gastric bypass, or traditional medical therapy and intensive lifestyle modification. All patients will be counselled in lifestyle modification techniques like diet and exercise.


Rubino said that he expects there will be medical advantages for patients in both arms of the trial since those assigned to the medical arm will receive the most rigorous medical diabetes therapy available. A multi-disciplinary team of diabetes and nutrition experts will take care of patients using the most current approved drugs for diabetes as well as an intensive approach to lifestyle changes. Patients in the medical arm will also be offered the chance to switch study arms and have surgery free of charge after the study is complete, or earlier should their diabetes remain poorly controlled after medical and lifestyle therapy.


"Understanding how gastric bypass surgery functions may help us learn how diabetes works" Francesco Rubino

Rubino and his co-investigators believe their study may also help identify better criteria than BMI for selection of surgical candidates. "Using strictly BMI-based criteria may be practical, but it is medically inappropriate because, on its own. BMI does not accurately define the severity of diabetes or identify patients who are best suited to benefit from a surgical approach. New criteria would not only help patients and clinicians, but also payers."


Because insurers use BMI-based criteria, bariatric surgery is currently not covered for patients with a BMI less than 35, regardless of the severity of their disease. Consequently, the study at NewYork-Presbyterian/Weill Cornell is supported by a research grant from the healthcare device and supply company Covidien covering the cost of surgery for patients enrolled in the study.


Previous research by Rubino studied how bariatric surgery alleviates diabetes, showing that the effect on diabetes is not entirely explained by a person's weight loss. The gastrointestinal tract serves as an endocrine organ and a key player in the regulation of insulin secretion, body weight and appetite, which is why altering the GI tract has such profound metabolic effects.


The current study aims to shed more light on the mechanisms of action of gastric bypass on diabetes. To do this, Rubino and his co-investigators will measure gut hormone responses to meal stimulation when an equivalent amount of weight loss has been achieved in both surgically and conventionally treated patients. This design may help uncover endocrine effects specific to gastric bypass surgery beyond those associated with non-surgical weight loss.

"Understanding how gastric bypass surgery functions may help us learn how diabetes works," said Rubino. "This knowledge has the potential to lead to the development of new minimally invasive procedures, devices interventions and better pharmaceutical treatments."


Rubino hopes that the current study will be a template for larger, international studies. "We intend this study to serve as a core protocol for similar randomised clinical trials independently run at other institutions as part of a worldwide consortium coordinated through the Diabetes Surgery Center at NewYork-Presbyterian/Weill Cornell," he said. "The consortium will provide a larger pool of patients allowing researchers to better evaluate the impact of surgery on various health measures, including cardiovascular risk and life expectancy."


Pilot study

In a separate study, physicians at the University of Texas Health Science Center at Houston (UTHealth) have begun enrolment for a pilot study for the management of Type 2 diabetes. Patients will undergo a ileal transposition with sleeve gastrectomy, which has been associated with encouraging results. If the procedure proves effective, it could allow some people with Type 2 diabetes to cut back or quit their medications.

"We’re not completely sure why people with morbid obesity and Type 2 diabetes experience this improvement following surgery" Brad Snyder

The objectives of the study include evaluating the safety of the procedure and determining its effectiveness compared to dietary and medical management of Type 2 diabetes. The UTHealth doctors plan to treat ten people with Type 2 diabetes surgically and ten medically. Participants will be followed over a two-year period and their outcomes compared.


“No one has compared this surgery directly to medical therapy in a randomized, prospective study like this,” said Dr Brad Snyder, the principal investigator of the study and an Assistant Professor of Surgery at the UTHealth Medical School. “We’re not completely sure why people with morbid obesity and Type 2 diabetes experience this improvement following surgery. It could be a combination of the different metabolism of food, the improvement of insulin action or the improvement in insulin secretion. This research will help us find some answers and could lead to future treatments.”


Metabolic and bariatric surgery is typically limited to people with a body mass index of 40 kg/m² or more, or a BMI of 35 kg/m² or more with an obesity-related condition in accordance with National Institutes of Health (NIH) parameters for bariatric surgery.

This pilot study for the surgical management of Type 2 diabetes is restricted to people with a body mass index (BMI) of 25 to 34 kg/m², which includes people who are overweight or obese. Participants must be between 21 and 55 years of age and being treated for Type 2 diabetes.


The clinical trial team includes Dr Philip Orlander, a Professor of Medicine and Director of the Division of Endocrinology, Diabetes and Metabolism at the UTHealth Medical School, who medically treats people with Type 2 diabetes. “The average person with Type 2 diabetes may be on 10 different medications to control their blood sugar, cholesterol and blood pressure,” Orlander said. “When we send people to bariatric surgery, a significant portion may be able to stop all of their diabetes, cholesterol and blood pressure medications.”


Dr Frank Moody, a professor of surgery at the UTHealth Medical School with a long time interest in the surgical treatment of digestive system diseases, is assisting the research team and said the study could shed light on hormones involved in the metabolic process. “The team will be looking at the impact of surgery on the processing of sugars by the diabetic subjects with an expectation of fixing the break in their metabolism,” Moody said.


The study is titled “A Surgical Approach to the Management of Type 2 Diabetes Mellitus in Patients with a BMI between 25-34 kg/m².” The study was approved by the UTHealth Committee for the Protection of Human Subjects and is anticipated to take about three years to complete. If successful, the next step could involve a large clinical trial.

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