A surgical cure for diabetic and obese patients

Feb 25 2010

Dr. Francesco Rubino, chief of gastrointestinal metabolic surgery at NewYork-Presbyterian Hospital/Weill Cornell Medical Center, is now enrolling overweight and mildly obese patients -- those with a body mass index (BMI) of 28 to 35 -- in a study of gastric bypass surgery aimed at reversing Type 2 diabetes. Because of their non-morbidly obese status, these patients do not qualify for the surgery under current guidelines.

Today, gastric bypass, along with other bariatric procedures, can only be prescribed for patients with a BMI of 35 and over.

"The relationship between obesity and Type 2 diabetes is complex and needs to be looked at closely," says Dr. Rubino, associate professor of surgery at Weill Cornell Medical College. "Despite the strong association between the two, they don't always go hand in hand. A significant number of people with lower BMI can develop diabetes and its life-threatening risks and complications. Conversely, a person may be severely obese, with all the risks and quality-of-life issues that accompany that condition, but diabetes-free. For this reason alone, we need to start questioning whether BMI should be the only clinically appropriate way to decide who gets diabetes-targeted surgery."

BMI became a parameter of eligibility for bariatric surgery about 20 years ago. A strict BMI cutoff makes sense when selecting candidates for bariatric surgery aimed at weight loss, but in Dr. Rubino's view, it is an arbitrary and even discriminatory measure for separating those who qualify for life-saving intestinal bypass surgery from those who don't.

"As an alternative," Dr. Rubino explains, "patients should be triaged based on the severity of their disease, their metabolic profile, and other predictors of cardiovascular disease risk."

Diabetes: A Surgical Cure?

A chronic disease that afflicts more than 200 million people worldwide, Type 2 diabetes takes a huge toll on those with the disease. Over time, many patients are faced with potentially deadly complications affecting the kidneys, eyes, heart and extremities. For many patients, unfortunately, treatments such as diet, hypoglycemic medications and insulin are ineffective, especially in the case of advanced disease.

Still, says Dr. Rubino, most of us don't think of diabetes as a surgically treatable condition. Diet and exercise go far toward preventing the disease, which is why he agrees that preventive and primary care should receive priority in the realm of health care policy and planning. The problem is that lifestyle changes around diet and exercise become less effective as the disease progresses and metabolic changes take on a life of their own and begin to ravage the body.

"Telling a patient with severe obesity or diabetes to diet and exercise is comparable to telling a person with lung cancer to stop smoking," says Dr. Rubino. "We all agree smoking is an important risk factor for lung cancer, but no one would suggest stopping smoking can cure the disease. Obesity and diabetes are often approached as if they were lifestyle issues, rather than established diseases, and this has influenced how we conceptualize the risks and benefits of therapies for diabetic and obese patients."

As one of the founders of the specialty known as gastrointestinal metabolic surgery, Dr. Rubino has tracked the benefits of bariatric procedures -- especially those that reroute rather than simply restrict the digestive tract -- when performed in severely obese patients with diabetes. He and his colleagues have found that immediately after intestinal bypass surgery, the disease improves radically, often to the point of complete remission. These results, he says, appear to be unrelated to weight loss.

Based on earlier studies and on clinical experience in other countries, Dr. Rubino and his colleagues have found that removing portions of the jejunum or duodenum -- the upper part of the small intestine right below the stomach -- leads to spontaneous improvement or even resolution of diabetes. The same holds true when the surgeon simply inserts a tube inside that part of the intestine, allowing food to pass through without coming into contact with the intestinal wall. Based on these findings, Dr. Rubino hypothesizes that when food passes from the stomach into the upper end of the small bowel of diabetic patients, it might trigger a cascade of hormonal reactions that cause diabetes. Understanding precisely how and under what circumstances such reactions occur is Dr. Rubino's longer-term research goal.

Remission of Diabetes

A substantial body of medical literature shows that many Type 2 diabetic patients who undergo gastric bypass surgery achieve normalization of blood sugars and can even discontinue their diabetes medications. "This phenomenon puzzles clinicians and scientists," says Dr. Rubino. "Is diabetes cured? What happens to it? We are left scratching our heads because this has no precedent in the history of diabetes treatments."

The idea of surgery as an approach with curative intent for diabetes has been gaining support. In the November 2009 issue of Diabetes Care, the official publication of the American Diabetes Association (ADA), a group of 12 clinical experts, including Dr. Rubino, published a consensus statement that defined diabetes remission as a condition where normal blood sugar levels can be maintained without the need for continuous pharmacological treatment. "This consensus statement implicitly recognizes that the only current intervention with potential for inducing remission of diabetes is surgery," says Dr. Rubino. "It is a huge conceptual shift if one considers that diabetes is typically regarded as a chronic and invariably progressive illness."

Broadening Access to the Surgical Option

At NewYork-Presbyterian/Weill Cornell, Dr. Rubino performs the standard Roux-en-Y bypass procedure in patients with a BMI over 35, who form the greater part of his practice. Most of them come to him seeking treatment for both obesity and Type 2 diabetes. Now, the potential benefits of intestinal bypass are being extended to 50 non-obese patients as part of the current study.

Dr. Rubino's efforts have already begun to affect a shift in diabetes treatment guidelines at the highest level. In 2007, he was the lead organizer of the first Diabetes Surgery Summit, held in Rome. The conference issued a set of recommendations, recently published in the Annals of Surgery, regarding the use of surgery as a diabetes-specific treatment. Additionally, the ADA has now recognized diabetes surgery as a viable option for people with BMI of 35-plus in a 2009 supplement to its Standards of Medical Care in Diabetes document. Both the ADA and the DSS consensus statement emphasized the importance of clinical trials to investigate the role of surgery in the treatment of diabetes in patients with a lesser degree of obesity.

Source: NewYork-Presbyterian Hospital/Weill Cornell Medical Center