By Robin Blackstone, MD, FACS, FASMBS

Introduction
If you are a person with type 2 diabetes there is a very good chance you are also overweight or obese. These two diseases seem to go hand in hand, with obesity preceding the development of pre-diabetes or diabetes. Obesity starts at a body mass index (BMI) of 30, which for a woman who is five feet, four inches tall, means she is about 30 pounds overweight. To calculate your BMI visit www.nhlbisupport.com/bmi. An ideal BMI is about 25 with 25-30 percent body fat.

Once your weight goes up and stays up for awhile, many people develop high cholesterol and high blood pressure and they also may become pre-diabetic (blood glucose between 100 and 125). If they lose the extra weight at this point, they may not go on to become diabetic, but if they don’t lose their weight or if they gain more weight eventually about 30 percent of obese people become diabetic. After someone is diagnosed with diabetes, many of the medications that are used to help control blood sugar actually make the person gain more weight, locking the person into a deadly cycle.

Over the last 15 years, it has become increasingly clear that weight loss surgery can improve type 2 diabetes (up to 80 percent of patients) or even, in some people, put the diabetes into remission.² Remission of type 2 diabetes means a normal blood sugar (less than 100), no diabetes medications and an HbA1C of less than 6.0. HbA1 is a test that measures the amount of glycated hemoglobin in blood.

In 2009, the American Diabetes Association guidelines included the consideration of bariatric surgery as part of the strategy for patients to gain control of their high blood sugars. Perhaps you are a diabetic patient who is also overweight or obese and you are wondering when or if you should consider using one of the bariatric procedures as part of your fight against this disease.³

What is Bariatric and Metabolic Surgery?
Surgery to help people control their weight also seems to help them control other metabolic problems like type 2 diabetes, high blood pressure and high cholesterol. Control of these three risk factors decreases the risk of heart and vascular disease, while also decreasing inflammation in the body.

There are four surgical procedures approved by the American Society for Metabolic and Bariatric Surgery and the American College of Surgeons that can be used to treat obesity and metabolic disease. The procedures can cause a restriction of calories, change the way in which hormones contribute to hunger and a feeling of fullness or re-route the food so that not all the food is absorbed (malabsorption). When the procedure causes malabsorption of calories, it also causes malabsorption of protein, vitamins and minerals, some of which have to be replaced. For the remission of type 2 diabetes, the most important question is whether the food goes through a part of the intestine called the duodenum. Those procedures are more effective in the management of diabetes. 

The chart below shows a comparison of these four procedures. 

Procedure	Restricts the amount of food	Affects Hormones	Food not absorbed	Bypass Duodenum	Risk
Adjustable Gastric Band	+++				Low
Sleeve Gastrectomy	++	++			Medium
Gastric Bypass	+++	++	++	Yes	Medium
Duodenal Switch/BPD	++	++	++++	Yes	High

The Risk/Benefit Equation
Is surgery safe? One of the key issues for using any therapy is how safe it is. A recent paper published in the New England Journal of Medicine showed the risk of death from bariatric surgery procedures is about the same as it is for gallbladder surgery.⁴ The risk of complications is higher than the risk of death. There are a few important issues to keep in mind about safety. First, when you have type 2 diabetes and other medical problems, you bring some risk to surgery. The healthier you are at the time of surgery the better you will do. Taking time to exercise, getting about 10 percent of your weight off and making sure your sugar is in as good control as possible are all very important. A good bariatric program is going to help you meet these goals. You need to be an informed consumer. The choice of surgeon and the program they work with is perhaps the single most important factor in avoiding complications. You want a surgeon who does at least 125 bariatric surgeries per year and works in a National Center of Excellence. These programs have to conform to national standards of care and have been site visited to confirm they have the right education, personnel and equipment to do the surgery safely. No surgical procedure is without risk, but risk can be managed.

For people whose BMI is less than 50 and who have pre-diabetes or have had diabetes for less than two years and are only on metformin (oral anti-diabetic drug), the options for surgery are broader. These people may be successful with a gastric band or a gastric sleeve, depending on their personal habits of eating and lifestyle. For people who have a BMI greater than 50 or who have had diabetes for more than two years and are on more than one medication, their best procedure is the gastric bypass. For these patients with diabetes the data shows having a gastric bypass will reduce the risk of death by 92 percent.⁵

What are the Effects of Surgery on Type 2 Diabetes, Hypertension and High Cholesterol?
Based on our current understanding of the data, for both the adjustable gastric band and sleeve gastrectomy, the results are entirely dependent on whether the patient loses weight. Many patients who are diabetic and have gastric bypass surgery go into remission of their diabetes a few days, weeks or months after their procedure, before significant weight loss occurs. 

What are the Effects on Chronic Kidney Disease 
Very little research has been done to determine the effect of surgery on patients who already have developed kidney disease from type 2 diabetes. One recent research study followed 45 patients with impaired kidney function who had a laparoscopic gastric bypass. Although no patients had resolution or improvement of their kidney function long term, two dialysis patients were able to discontinue dialysis for 27 and seven months and the remaining patients had stable disease for two to five years.⁶

Summary

In summary, the goal of the management of type 2 diabetes is glucose control at a level that prevents the sugar in the blood from damaging organs including the kidneys. All forms of control, whether medical or surgical, have defined risks. For a patient who also has other metabolic disease, like obesity, high blood pressure or high cholesterol and lipids, surgical treatment of type 2 diabetes and other metabolic disease may be achieved with relative safety through bariatric surgery. Talk to your family doctor, an endocrinologist or diabetologist to help you make a reasonable choice about what therapies are most appropriate to manage your diabetes. Certainly, if you are obese, have diabetes and your medication is not helping to control the diabetes, surgery is an important option to consider. If you are going to seek surgical options, do thorough research to find the right program and doctor. Make sure the surgeon and program you pick offers at least the three most common procedures and they are performed through small laparoscopic incisions. The program you choose should be a recognized Center of Excellence in Bariatric Surgery by the American Society of Bariatric Surgeons (www.ASMBS.org) or the American College of Surgeons (www.acsbscn.org). 

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