Can Bariatric Surgery Be A Cure For Type 2 Diabetes In Obese Patients?

   In recent years, there have been numerous studies that demonstrate the link between obesity and type 2 diabetes. Several studies have demonstrated that modest weight loss in at-risk patients with impaired glucose tolerance reduces the incidence of new diabetes nearly 60 percent over four years.1

   Furthermore, research has documented that weight loss improves metabolic control in these patients.2 Research also demonstrates that remission of diabetes is possible in those individuals who demonstrate sufficient reduction in body mass index (BMI).1 Clearly, weight loss is beneficial in obese patients with type 2 diabetes.

   However, such necessary weight loss is difficult to achieve and is perhaps even more difficult to maintain. It is this challenge that has prompted clinicians to seek out alternative treatment options to promote weight loss in this challenging patient population. In this regard, bariatric surgery has shown significant promise.

A Closer Look At The Numbers On Diabetes And Comorbidities

   There are nearly 24 million Americans living with diabetes, approximately 8 percent of the total population. Nearly 6 million of these individuals are undiagnosed.2,3 Current estimates suggest that by 2050, 48 million Americans will have type 2 diabetes.2

   The incidence of type 2 diabetes in adolescents has increased 10 times over the last decade and now constitutes just less than one-third of new pediatric diabetes cases. In contrast, type 2 diabetes accounted for only 20 percent of all pediatric cases a decade ago.2 This is an epidemic of diabetes that we cannot ignore.

   There have been numerous studies that demonstrate the link between diabetes and other medical comorbidities. Of those with diabetes, 60 percent of patients demonstrate one other serious health problem; 33 percent of patients demonstrate two other serious health problems; 10 percent have three other serious health problems, and 7 percent have four or more additional serious health problems.4

   Diabetes is a leading cause of adult blindness, lower limb amputation, kidney disease, nerve damage and cardiovascular disease. Diabetes is particularly common among those patients who are morbidly obese and these patients commonly demonstrate a metabolic syndrome that includes type 2 diabetes, hypertension, hypercholesterolemia and elevated triglyceride levels.

   In addition, this epidemic of diabetes demonstrates significant economic consequences that should be of major concern to both healthcare providers and healthcare consumers.

   The total annual cost of diabetes has been estimated at $174 billion and most experts agree that this value is an underestimate. Of this total, $116 billion constitutes direct medical costs, which are associated with hospital stays, medications and medical equipment. The remaining $58 billion are indirect costs, which include the expense of disability, premature mortality and work loss.4-7 Furthermore, experts suggest that obesity will cost the United States approximately $344 billion in medical related expenses by 2018. This would constitute approximately 21 percent of all healthcare spending.8

   Clearly, the healthcare profession must make significant efforts to address this rising epidemic of diabetes and diabetes-related complications in order to reduce morbidity and mortality in patients living with diabetes, and help reduce the spiraling healthcare costs.

Weighing The Pros And Cons Of Bariatric Surgical Procedures

   When considering bariatric surgical procedures, there are essentially two categories: gastric restrictive procedures and those procedures that introduce an element of malabsorption.

   Gastric restrictive procedures limit the capacity for food intake by creating a small pouch from the proximal stomach that limits the passage of solid foods (although liquids empty normally), and weight loss then progresses from a process of dietary re-education.1,9-11 A current example of such a procedure would be a laparoscopic gastric banding, which demonstrates a safety record and operative mortality now approaching zero in many large series in centers that perform large numbers of these procedures.

   Malabsorption procedures, often utilized in conjunction with elements of gastric restriction, demonstrate greater weight loss outcomes than gastric restriction alone.12,13 Traditionally, however, these procedures demonstrate significantly higher long-term complication rates with patients exhibiting an increased incidence of protein and vitamin malabsorption syndromes, osteoporosis and liver failure.14,15

   Consequently, these increased adverse outcomes created a stigma on bariatric surgical procedures that has persisted despite improved overall outcomes. Advances in surgical techniques, such as laparoscopy and postoperative micronutrient replacement therapies, have significantly reduced the overall risk for this type of procedure to less than 1 percent in experienced hands.16,17

What The Literature Says On The Efficacy Of Bariatric Surgery

   While one should not lightly consider referring patients for possible bariatric surgery procedures, patients undergoing these types of bariatric procedures have reportedly had significant remission rates of their diabetes.18

   One study demonstrated remission rates of 82.9 percent for 165 patients with type 2 diabetes for an average of 14 years following Roux-en-Y gastric bypass surgery.19 A meta-analysis of 22,094 patients showed that 84 percent of patients experienced complete reversal of type 2 diabetes following bariatric procedures with most stopping their oral medications or insulin injections before leaving the hospital.20

   More recently, an article in the Journal of the American Medical Association (JAMA) focused on patients with diabetes who underwent gastric banding combined with conventional therapy (defined as lifestyle modification, increased physical activity and occasional medical therapy).21 Seventy-three percent demonstrated a remission of diabetes symptoms defined as normal blood sugar levels with no need to use supplemental insulin or oral hypoglycemic therapies. In contrast, only 13 percent of those individuals who received conventional therapy alone achieved remission of their diabetes.

   There have been numerous proposed mechanisms of action to explain the observed remission rates of diabetes following bariatric surgery.22-27 Originally, researchers believed the improvement in diabetes symptoms was due simply to patient weight loss. However, more recent research has demonstrated that within a week of surgery, improved insulin sensitivity and blood glucose levels occur in patients with diabetes. This suggests that bariatric surgical intervention promotes a positive metabolic change prior to any actual weight loss.28,29

   While the specific mechanism is elusive, one can conclude that following bariatric surgery, patients with diabetes benefit from both improved metabolic function as well as overall long-term weight loss.

   Patient selection is of key importance in the determination of which patients may benefit from these types of bariatric procedures. Traditionally, bariatric surgery has been limited to those patients who are considered morbidly obese with a BMI of 40 kg/m2, or in patients with a BMI of >35 kg/m2 and one or more significant comorbid conditions.22

   In patients with diabetes, there is a consensus that bariatric surgery should be reserved for those individuals with a BMI >35 kg/m2.29 In patients over 60 years or in children and adolescents, bariatric surgery is not recommended because long-term outcomes in these patient populations have not undergone extensive testing.

   Furthermore, there is evidence to suggest that those patients who present for surgery with a more recent onset of diabetes (less than five years) are more likely to demonstrate diabetes remission postoperatively.27

In Conclusion

   In recent years, there has been substantial research and literature that demonstrates that, in certain instances, patients suffering from type 2 diabetes can achieve full remission of their symptoms following bariatric surgery. A weakness thus far in these studies is that these results come from patients with diabetes who have undergone bariatric procedures primarily for other reasons.

   Does bariatric surgery provide the option of a cure for type 2 diabetes? Certainly, it can in certain patient groups. For younger patients with a relatively recent onset of diabetes and BMI over 35, the literature demonstrates that bariatric surgery can provide a significant treatment option.

   However, further studies are required before we can recommend these bariatric treatment modalities to patients as a primary method of managing their diabetes.

   As clinicians involved in the interdisciplinary management of patients with diabetes, it is incumbent that podiatric physicians be versed in all manner of developing treatment options that may be available to our patients.

   The current data on bariatric surgery is promising and further evidence-based trials may indeed prove this treatment is the cure that will save millions of limbs and lives.

Dr. Fitzgerald is an Associate of the American College of Foot and Ankle Surgeons. He practices at Hess Orthopaedics and Sports Medicine in Harrisonburg, Va.

Dr. Steinberg is an Assistant Professor in the Department of Plastic Surgery at the Georgetown University School of Medicine in Washington, D.C. Dr. Steinberg is a Fellow of the American College of Foot and Ankle Surgeons.

For further reading, see “Can A Gastric Bypass Procedure Have A Positive Impact On Diabetes?” in the July 2006 issue of Podiatry Today.

References:

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