Metabolic Surgery: Surgical Treatment for Type 2 Diabetes
Diabetes is a chronic metabolic disorder that occurs when the body does not produce enough insulin and/or cannot effectively use the insulin it produces (a condition referred to as "insulin resistance"). Inadequate insulin production and action lead to raised blood glucose levels (hyperglycemia), which can adversely affect various organs and tissues including the heart, kidneys and eyes. Type 2 diabetes is associated with various cardio-metabolic disorders including obesity, high blood pressure (hypertension) and increased blood cholesterol and triglycerides (dyslipidemia).
Type 2 diabetes is a progressive disease, characterized by continuing deterioration of insulin secretion over time. This leads to increasing need for medication, while persistent or worsening glycemic control may increase the risk of developing diabetes complications (i.e. hearth attacks and strokes, kidney failure, eye disease and blindness etc).Although the exact underlying causes of type 2 diabetes are not yet fully understood, a number of risk factors have been identified. These include: obesity, diet, lack of physical activity, increasing age, insulin resistance, family history of diabetes and ethnicity.
Bariatric surgery, however, results in dramatic improvement of type 2 diabetes, hypertension, dyslipidemia, and reduction of overall mortality. Experimental studies from our center show that the anti-diabetes effect of certain bariatric procedures, particularly gastric bypass surgery, results from mechanisms that go beyond weight loss alone. Surgical treatment of type 2 diabetes may be offered to less obese patients with excellent results.
Metabolic and Diabetes Surgery
The recognition that mechanisms and benefits of bariatric surgery extend beyond weight loss question the appropriateness of the name bariatric surgery, which reflects only the goal of weight-reduction. In fact, the concept of "metabolic surgery" has emerged to indicate a surgical approach aimed at control of metabolic illnesses, not just excess weight.
Metabolic surgery includes surgery for diabetes (indeed the term “diabetes surgery” is gaining recognition), surgery for obesity and metabolic syndrome, and also surgery for weight reduction when weight per se represents a significant burden on quality of life.
Approximately 80% of patients operated on in our program have at least one metabolic disorder such as type 2 diabetes, hypertension, increased lipids or sleep apnea.
Severely obese women have an estimated 93-fold higher risk of developing type 2 diabetes, while severely obese men have an estimated 42-fold higher risk compared to people of healthy weight. Obesity also contributes to the metabolic syndrome – the dangerous cluster of heart attack risk factors that includes central (abdominal) obesity, hypertension and dyslipidemia.
In severely obese individuals, surgery can cause "remission" of diabetes in the majority (normal blood sugars without medications) and significant "improvement" in blood glucose in others (improved blood sugars with lesser medication).
Approximately, 40-50% of morbid obese and diabetic patients who have laparoscopic gastric banding achieve remission of type-two diabetes. With gastric bypass or biliopancreatic diversion, the rate of remission is reported to be superior ~ 70-80%.
In addition to providing excellent control of diabetes and weight loss, gastrointestinal metabolic surgery has several additional benefits, including improvement of hyperlipidemia, hypertension and sleep apnea. Moreover, the incidence of cancer is reduced in obese patients who have had bariatric surgery. Most importantly, several reports have consistently shown that in patients with diabetes and severe obesity, surgery increases long-term survival.
Why is it difficult to treat diabetes by medical therapy?
Significant weight loss through lifestyle modification and medical methods is modest at best and is rarely sustained in obese, and particularly severely obese people. Medical options for controlling blood glucose levels are also unfortunately less effective in severely obese people. In addition, a number of medications used for treating type 2 diabetes, including insulin, can result in weight gain. When diabetes is difficult to control, especially in patients with severe obesity, surgery should be considered as a valuable option to achieve control of blood sugar and reduction of cardiovascular risk factors.
A position statement of the International Diabetes Federation recommends that surgery be considered early in the management of disease in obese patients, and not only as a last resort.