Diabetes and Weight-Loss Surgery

Transcription

1 WHITE PAPER Diabetes and Weight-Loss Surgery Treat the cause. Cure the symptom. Center of Excellence BARIATRIC SURGERY Written July 2011

2 Bariatric Surgery: The Cure for Type II Diabetes? For most individuals suffering from diabetes mellitus (type II), morbid obesity is the major underlying cause. According to the American Diabetes Association, almost 90 percent of people newly diagnosed with diabetes are overweight. Obesity is the disease; diabetes is the symptom of the disease. As with any other disease, it is almost always better to treat the primary disease rather than just the symptom. Science has long proven that losing weight can improve type II diabetes. Now there is increasing evidence that bariatric surgery will significantly improve type II diabetes in most patients, and in many cases, will completely reverse it. Even as scientists work to completely understand the biological mechanisms that make some surgical procedures so successful at controlling diabetes, the patient success stories continue to multiply. So what do physicians need to know before presenting bariatric surgery as a treatment option to morbidly obese diabetic patients? In this white paper, we will examine: The growing evidence linking bariatric surgery to type II diabetes remission How bariatric surgery works to reverse diabetes Why gastric bypass is more successful at reversing type II diabetes than other procedures Which diabetic patients are candidates for bariatric surgery How the risks of bariatric surgery compare to the benefits The Growing Evidence While the phenomenon can t exactly be called a scientific miracle, thousands of former type II diabetics say that the effects on their health and quality of life have been nothing short of miraculous. As a result of successful bariatric procedures, these patients have lost more than just weight they have also lost their need for insulin shots and constant diabetic care and in a short amount of time. There are now more than 30 clinical studies linking bariatric surgery to type II diabetes resolution, including: In a study of more than 2,200 U.S. adults 1, Johns Hopkins University researchers found that nearly 3 out of 4 patients were able to stop taking their insulin and other diabetes medications within six months of surgery. Two years after the operation, almost 85 percent were off diabetes medications as a result of improved blood glucose levels. In a 2009 analysis of more than 600 studies involving over 135,000 patients, 78 percent of patients with type II had complete resolution of their diabetes after surgery, and 87 percent had improved blood glucose levels. 2 1 "Weight-Loss Surgery May Cut Type II Diabetes Medication Use." Drugs.com Prescription Drugs - Information, Interactions & Side Effects. 16 Aug Web. 12 May < html>. 2 Gebel, PhD, Erika. "Weight-Loss Surgery and Type II Diabetes." Diabetes Forecast Magazine. Mar Web. 12 May < 1

3 In a landmark 2004 JAMA study that followed 22-thousand people who underwent bariatric surgery, type II diabetes was completely resolved in 76.8 percent of people, and it improved in 86 percent of people. The bariatric surgery procedures performed in this study included gastric banding, gastric bypass, gastroplasty, biliopancreatic diversion or duodenal switch, and others (such as jejunoileal bypass, a bypass of a section of the small intestine). 3 How it Works Bariatric surgery achieves weight loss by restricting food intake and, in some cases, preventing the absorption of food in the small intestine. There are three main types of weight-loss surgery that help restrict food intake in different ways: Gastric banding During this procedure, the surgeon uses laparoscopic tools to place an adjustable silicone band around the upper part of the stomach. Once this part of the stomach is restricted by the silicone band, the entire stomach becomes a pouch with about an inch-wide opening. Typically, after the band is successfully adjusted, the stomach can only hold about one ounce of food. This helps patients to feel full faster, eat less, and lose weight. On average, patients can expect to lose about 40 percent of excess weight after gastric banding surgery. Sleeve gastrectomy During this surgery, which is typically performed laparoscopically, the left side of the stomach, or greater curvature, is removed. The stomach that results from this procedure is often compared to the size and shape of a typical banana. Because the new stomach continues to function normally, there are far fewer restrictions on the foods which patients can consume after surgery, although the quantity of food eaten is considerably reduced. And because the fundus of the stomach is removed the area that secretes hormones that make you feel hungry a sleeve gastrectomy often helps patients to feel less hungry through a hormonal mechanism. Roux-en-Y gastric bypass In this 60- to 90-minute procedure, the surgeon sections off a portion of the stomach and reroutes part of the small intestine. This helps patients lose weight not only by restricting food intake, but also by limiting calorie absorption in the intestines. Typically, patients who undergo gastric bypass surgery can expect to lose 50 to 60 percent of excess weight in the first two years following the procedure. 3 Buchwald MD, Henry, et al. "Bariatric Surgery: A Systematic Review and Meta-analysis." JAMA, the Journal of the American Medical Association (2004): Oct Web. 19 May < 2

4 Following each procedure, smaller stomach capacity and reduced hunger levels result in patients consuming fewer calories and refined carbohydrates which in turn, leads to stabilized blood sugar levels. As patients begin to lose significant weight, their insulin resistance is also improved. Gastric bypass patients have shown more than 83 percent resolution in type II diabetes, making it the most effective bariatric surgery option for diabetics. In addition, more than 90 percent of type II diabetics experience excellent post-surgery results. This includes normal blood sugar levels, normal Hemoglobin A 1C values, and freedom from all medications, including insulin injections. The gastric band and the sleeve gastrectomy have also proven to resolve diabetes, though it typically takes longer to see the results. Each procedure has its own risks and benefits that must be carefully weighed on a case-bycase basis. For instance, gastric bypass is permanent and more invasive than gastric banding, which is performed with less invasive surgery and can be reversed. What Makes Gastric Bypass More Effective at Resolving Diabetes Through a mechanism that scientists are still trying to understand, diabetic patients who undergo gastric bypass (and often sleeve gastrectomy) procedures experience improved glycemic control almost immediately after surgery even before they lose any weight. A recent study from Duke University Medical Center and Columbia University compared patients who had gastric bypass surgery to a group of patients who were dieting. Both groups lost about the same amount of weight (20 pounds), but those who received the surgery saw a significant decrease in their blood glucose levels. They also had much lower levels of amino acids called branched-chain amino acids compared with those who lost the weight through dieting. These types of amino acids have been associated with insulin-resistance and heart disease. One month after surgery, all of the gastric bypass patients were off all diabetes drugs. 4 Something about the surgery, not the weight loss itself, seems to be improving glycemic control and researchers believe that amino-acid levels may have a role. But it is unclear if the amino acids cause lower resistance to insulin. Two cardiologists from Massachusetts General Hospital write in a related Perspective: Further work is needed to establish whether the reduction in concentrations of circulating amino acids after weight loss is the cause or consequence of improvements in insulin sensitivity. 5 Which Diabetic Patients are Bariatric Surgery Candidates The body of evidence pointing toward bariatric surgery as a possible cure is certainly encouraging for patients suffering from type II diabetes. However, the findings do not mean all obese people with 4 Boyles, Salynn. "Gastric Bypass May Improve Diabetes Quickly." WebMD Diabetes Center. 27 Apr Web. 12 May < 5 R. E. Gerszten, T. J. Wang, Two Roads Diverge: Weight Loss Interventions and Circulating Amino Acids. Sci. Transl. Med. 3, 80ps15 (2011). 3

5 diabetes should pick surgery over dieting. Even the most minimally invasive surgical procedures come with some risks, and not everyone is a candidate. In March 2011, the International Diabetes Federation, which represents more than 200 diabetes groups across the globe, called for weight-loss surgery to be considered a treatment for type II diabetes in certain patients with a body mass index (BMI) as low as Currently the National Institutes of Health guidelines recommend bariatric surgery for patients with a body mass index (BMI) over 40. Gastric banding is now approved for people with BMIs between 30 and 40 if they have obesity-related illnesses such as diabetes. Other weight loss surgeries are only recommended for people with diabetes whose BMI is greater than Ultimately, each potential candidate must be considered on a case-by-case basis, looking at the patient s overall physical and mental health, weighing the benefits against the risks for that individual. Surgical candidates must be prepared to make a long-term commitment to diet and lifestyle change following surgery. Patients must understand that even following bariatric surgery, lost weight can be regained if restrictions and recommendations are not followed. And if type 2 diabetes goes into remission as a result of weight loss, it will likely come back when the weight returns. Risks vs. Benefits There is little doubt that both morbid obesity and type II diabetes, if left untreated, can lead to death. In a study published in the Annals of Surgery in , researchers compared outcomes of nearly 8,200 gastric bypass surgery patients. After nearly 20 years, the study showed: Those who underwent gastric bypass surgery were 53 percent less likely to have died prematurely than people with morbid obesity who did not have surgery. Those who had surgery were 88 percent less likely to die from diabetes; 64 percent were less likely to have died from cancer compared to those who did not have surgery. Yet, surgery is never a risk-free solution. The risk of death at experienced bariatric surgery centers is less than 0.3% (1 out of 300 patients), but it is a risk nonetheless. Death is usually due to a patient s health problems such as heart or lung disease. Surgical causes of death can be related to pulmonary embolism (blood clots to the lungs) or a gastrointestinal tract leak. Patients with a very high BMI, male patients, and patients with severe medical conditions are at the highest risk, but death can occur in any patient. 6 Mann, Denise. "Is Bariatric Surgery a Cure for Diabetes?" Yourbariatricsurgeryguide.com - Consumer Guide to Bariatric Surgery. 17 Feb Web. 19 May < 7 Christou, Nicolas, et al. "Surgery Decreases Long-term Mortality, Morbidity, and Health." Annals of Surgery (2004): Annals of Surgery. Oct Web. 19 May < idity,.3.aspx>. 4

6 In addition, each type of bariatric surgery has its own possible complications and side effects that patients and their physicians must consider. For example, post-surgical gastric bypass patients can have trouble absorbing enough vitamins because parts of the intestine that help the body absorb food are bypassed. Indeed, the reason for the decrease in blood amino acid levels in the patients after surgery may be malabsorption of protein, said Dr. Sunil Bhoyrul, a bariatric surgeon at Scripps Memorial Hospital in La Jolla, Calif. 8 But for a patient with longstanding severe diabetes, the risks of malabsorption from gastric bypass or complications during surgery might be outweighed by the potential cure for a life-threatening condition. For a relatively small, short-term risk, obese diabetic patients now have the possibility of obtaining a very large, long-term benefit that is truly life-changing. 8 Rettner, Rachael. "Why Weight-Loss Surgery Mysteriously Reverses Diabetes in Some Patients Gastric Bypass Surgery Type 2 Diabetes My Health News Daily." MyHealthNewsDaily.com. 27 Apr Web. 19 May < 5