Type 2 diabetes, often associated with obesity, is one of the most rapidly emerging health crises in our community. For many years, the goal in treating type 2 diabetes has been to use medication and lifestyle changes to control this chronic disease. Mild disease has been treated with oral medication while injectable insulin was used for more severe disease. Such conventional therapies were used without any intent to cure the underlying diabetes; rather, the therapeutic goal was to achieve medical control of blood sugar levels. Recently, however, there has been a fundamental advance in our understanding of this widespread disease. New data suggest that the use of metabolic surgery – historically used to treat obesity but now used as an intervention for type 2 diabetes – may result in better control of blood sugar, and even in complete remission of the disease.
The ability of the gastric bypass operation to improve diabetes has been recognized for many years. Studies from the early 1990s showed that over 80% of type 2 diabetics who underwent the operation maintained normal blood glucose levels after surgery – they were essentially cured of their diabetes. Interestingly, control of blood sugar levels was not dependent upon weight loss as might have been expected. Rather, the improvements in blood sugar occurred within several days after the operation, before any significant weight loss occurred. This finding suggested that the “rerouting” of the gastrointestinal tract that occurs in gastric bypass was directly responsible for the metabolic impact of the operation.
Despite this knowledge, the explanation of why gastric bypass operation cured diabetes was unclear until 2006, when Francesco Rubino published the results of his groundbreaking experiments on diabetic rats. When these rats underwent duodenal-jejunal bypass, an operation in which the intestines are rearranged so that no food passes through the upper part of the small intestine, their diabetes was remarkably improved. However, when their intestines were later reconnected so that food once again passed through the small intestine, the diabetes returned. This experiment led to the hypothesis that stimulation of the upper small intestine is directly related to the control of diabetes.
Metabolic surgery for humans took a tremendous leap forward in April of this year, when 2 landmark trials were published in the New England Journal of Medicine in which metabolic surgery was directly compared to traditional medical therapy for type 2 diabetes. In the first study, patients with type 2 diabetes were randomized into 2 groups; the first group underwent gastric bypass metabolic surgery while the second group received conventional medical therapy. Three-quarters of the surgical patients had full remission of their diabetes, while not one of the medically-treated patients did. In the second randomized prospective study, medical therapy alone was compared to surgical and medical therapy together. More than 3 times as many patients in the surgery group enjoyed full control of their diabetes when compared to the medical group.
At Mount Sinai, the Division of Metabolic, Endocrine and Minimally Invasive Surgery continues to look into methods of using surgery to control or cure type 2 diabetes. We currently perform minimally invasive operations, including laparoscopic gastric bypass, laparoscopic sleeve gastrectomy, and laparoscopic adjustable gastric banding on a daily basis to put type 2 diabetes into complete remission. While the operations are currently being performed on obese patients only, with a body mass index of 35 or greater, we are aiming to treat diabetic patients in lower weight categories as well. With new data emerging every month, we are hopeful that type 2 diabetes will soon become a disease which is not only chronically managed, but surgically cured.
Daniel Herron, MD, FACS
Chief, Section of Laparoscopic and Bariatric Surgery
Division of Metabolic, Endocrine and Minimally Invasive Surgery