Brief Overview of Metabolic Surgery

Putting the word “Cure” into the Management of Obesity-Induced Metabolic Disease

Obesity-induced metabolic diseases (OIMD) such as diabetes, hypertension and chronic fatigue are traditionally thought of as treatable, but not as curable. Lifelong therapy for these diseases is expensive, has numerous adverse side-effects and is only partially effective. The best treatment for obesity-induced disease has always been weight loss, but permanent weight loss is difficult to achieve. Nevertheless, l

ong-term weight loss and improved fitness can result in complete resolution of obesity-induced metabolic disease (OIMD).

The Cost of OIMD

Medications required to treat metabolic diseases are expensive and add up to considerable sums over a lifetime. The annual direct cost of treating the 67 million Americans (CDC, 2011) with hypertension was estimated at $47.5 billion, or about $710 per patient, adding up to more than $21,000 over thirty years. The $21,000 in direct costs does not account for the cost of all the additional diseases, such as kidney failure, stroke and heart disease, that develop as a result of long-standing hypertension.

Direct medical costs for treating the more than 25 million Americans (CDC, 2011) with diabetes is estimated at $176 billion, or $6,800 annually per patient, or over $200,000 per patient over 30 years. And, as a leading cause for stroke, heart failure, heart attack, kidney disease, blindness and amputation, the overall cost of diabetes are astronomical.

All the above costs are alarming, but if we take into account the socioeconomic costs of missed work, lost wages, time commitment of caregivers, and the cost of human suffering, the real price tag for OIMD is staggering.

The Role for Surgery

Metabolic surgery is the specialty of surgery that addresses OIMD as potentially curable. Historically, metabolic surgery has mainly focused on severe obesity and the operations have been primarily targeted towards weight loss. Over the past three decades, however, it has become increasingly apparent that the operations used for weight loss have a significant positive impact on several other metabolic disorders. In fact, the success in resolving hypertension, hyperlipidemia and type-2 diabetes through weight loss surgery has been so profound that new areas of research have developed concerning the role of the gastrointestinal tract in the management of metabolic disease.

The most exciting clinical revelation has been that performing gastrointestinal surgery to treat OIMD can, in fact, result in a cure. The potential for metabolic operations to actually cure these diseases is now an irrefutable fact, and has resulted in a paradigm shift where certain OIMDs should no longer be assumed to be lifelong illnesses. (Many debate this issue, but if a disease is simply not present, by all standard medical testing, then it is by definition cured.)

Published in the Journal of the American Medical Association in 2004, a meta-analysis of 22,049 patients that had undergone traditional bariatric surgery showed an overall 61% sustained excess body weight loss. In terms of OIMD the study showed a 76.8% resolution of type-2 diabetes, a 61.7% resolution of hypertension, and a 79.3% improvement in hyperlipidemia. In a more recent study examining 23,000 patients with metabolic syndrome that underwent bariatric surgery, 36%, 50% and 35% had complete remission of hypertension, diabetes and dyslipidemia, respectively.

The fact that diseases previously thought of as only treatable are now known to be potentially curable is incredibly important. Patients suffering from OIMD should now be counseled that there is an opportunity for cure. In fact, in my professional opinion, if a patient meets the criteria for metabolic surgical therapy, it is now below the standard of care for a physician counseling that patient to fail to make them aware of the possibility for surgical treatment of their disease.

Who Qualifies for Metabolic Surgery?

The National Institutes of Health (NIH) published guidelines for bariatric surgery after a 1991 consensus conference. These guidelines are currently published on their website with a disclaimer (reprinted below) stating that the guidelines are outdated. Despite advancements over the past 25 years resulting in safer bariatric procedures (decreased risk) and a higher level of success (improved benefit), Medicare and commercial insurers have refused to update the guidelines and still refer to the 1991 guidelines when authorizing payment for these surgeries.

The 1991 NIH guidelines were based on an extensive benefit-versus-risk analysis, and are fairly simple; “patients whose BMI exceeds 40 are potential candidates for surgery if they strongly desire substantial weight loss, because obesity severely impairs the quality of their lives. In certain instances less severely obese patients (with BMI’s between 35 and 40) also may be considered for surgery. Included in this category are patients with high-risk comorbid conditions” and patients with “obesity-induced physical problems interfering with lifestyle (e.g., joint disease treatable but for the obesity, or body size problems precluding or severely interfering with employment, family function, and ambulation).”

This disclaimer is included on the NIH website: http://consensus.nih.gov/1991/1991gisurgeryobesity084html.htm

“This statement is more than five years old and is provided solely for historical purposes. Due to the cumulative nature of medical research, new knowledge has inevitably accumulated in this subject area in the time since the statement was initially prepared. Thus some of the material is likely to be out of date, and at worst simply wrong.“

It’s unfortunate that a national agency is unwilling to update their published guidelines on such a widespread disease. The only explanations I can come up with are that there is a concern that up-to-date guidelines would result in an increased demand for weight loss surgery, or simply that ignoring the plight of obese people is still an acceptable bias in our society. The good news is that individual experts and professional organizations have updated their guidelines over time.

Following these 1991 guidelines, the insurance industry will generally authorize payment for bariatric surgery if patients have a BMI>40, or a BMI = 35-40 with significant weight-related disease or disability.

More up-to-date guidelines for metabolic surgery take into account the preponderance of scientific data showing that most patients with a BMI of 30 or greater have a markedly increased risk for OIMD including diabetes, heart disease, cancer and physical disability. They also take into account the lack of adequate alternative treatments for obesity. In fact, the health risks for a BMI of 30 or greater is so well accepted that the FDA approved the Lap-Band device for treating patients with a BMI as low as 30.

In my opinion, based on the safety and success of modern metabolic surgical procedures, it is now reasonable to offer weight-loss surgery for any patient with a BMI>35, and to all individuals with a BMI between 30 and 35 who have failed at long-term weight loss and complain of a significantly decreased quality of life, or who suffer from weight-related disease.

Education: The First Step

The first step in the metabolic surgery process is education of the patient and a reality check. When performed by experts in the field, metabolic surgery has a high degree of success and a low risk of major complications. However, patient willingness to make lifestyle changes is the key to obtaining long-term success. And, because the only reasonable goal for someone undergoing metabolic surgery is to achieve long-term or permanent success, up-front understanding of the patient role in the surgical treatment process is mandatory.

All patients need to be explained that maximum long-term success is dependent on lifestyle changes that they should find to be far easier to achieve with the help provided through surgery. Patients need to have it clear in their mind that, for long-term success, healthy changes in eating behavior need to be embraced. Healthy eating takes understanding and effort whether a person has been overweight or not, and only those patients that use the surgical procedure to assist them in improving their diet will succeed. The scientific literature is also fairly clear on the fact that long-term success is dependent on patients embracing a physically active lifestyle including daily exercise. Studies have shown that the surgical patients that use their surgically induced weight loss to pursue an active lifestyle that includes exercise obtain the best result.

What are the Standard Metabolic Surgical Procedures?

Bypass Operations:

A very brief history of bariatric surgery begins in 1953 with Dr. Victor Hensrikson of Gothenburg, Sweden who performed an intestinal resection to treat obesity, and with Dr. Richard Varco, at the University of Minnesota, who performed the world’s first intestinal bypass to treat obesity. For the next 25 years operations for obesity consisted primarily of malabsorption operations, specifically various kinds of intestinal bypasses; the jejuno-ileal bypass being the most common. These operations resulted in a high degree of malnutrition and fell out of favor in the 1970s. In 1967 a less malabsorptive operation was invented by Dr. Edward E. Mason at the University of Iowa, the Gastric Bypass, and this operation has been improved over the last 50 years to the current Laparoscopic Roux-en-Y Gastric Bypass which is still considered to be the gold standard bariatric operation. However, as a result of the complications seen with intestinal bypass, the term “bypass” came to falsely represent operations with a high risk of severe malnutrition. The gastric bypass involves only a limited intestinal bypass, mainly bypassing the stomach, whereas operations that carry a higher risk for malnutrition are those that bypass of a substantial portion of small intestine. Two operations that involve substantial intestinal bypass, the Biliopancreatic Diversion (BPD) introduced by Dr. Nicola Scopinaro in 1979 at the University of Genoa, Italy, and the Duodenal Switch (DS) designed by Dr. Douglas Hess of Ohio in 1986, are still performed by some surgeons. The BPD and DS operations are remarkably effective operations for treating diabetes and severe dyslipidemia (high cholesterol and high triglycerides), but carry with them a higher risk for malnutrition.

Restrictive Operations:

Around 1979 Dr. Mason also invented the gastroplasty, which carried no risk for malabsorption and was called a “restrictive operation” because it forced patients to eat slowly and chew well. Various forms of gastroplasty (also called “stomach stapling”) were used for about 20 years but, despite successful weight loss, the complications including chronic vomiting were high and the operations fell out of favor. In the 1990s, laparoscopic adjustable gastric banding was started in Europe and in 2001 the FDA approved the Lap-Band System™, for use in the United States. The Lap-Band turned out to be a very safe operation, and surged in popularity for more than ten years, but its popularity has since declined. The popularity of the Lap-Band has been replaced by the popular “sleeve” procedure which has weight loss comparable to the gastric bypass, but with no intestinal bypass so the risk of malabsorption is minimal.

Currently, the most common operations in the world are the sleeve gastrectomy, the gastric bypass and the Lap-Band, all performed using minimally invasive surgery (laparoscopy). The graph below demonstrates some of the differences between these operations. (Data specific to Dr. Quebbemann)

Procedure	Gastric Bypass	Sleeve Gastrectomy	Lap-Band
Average Length of Operation	50-60 minutes	30-45 minutes	30-45 minutes
Typical Hospital Stay	1 day	Outpatient or 1 day	Outpatient
Average Weight Loss	75% of excess(40-100%)	70% of excess(40-100%)	50% of excess(0-100%)
Significant Nutritional Issues	Uncommon	Uncommon	Rare
Nutritional Supplements	Highly Recommended	Highly Recommended	Recommended
Reversibility	Yes	No	Yes

Observations on Metabolic Surgery and Future Directions

Although it may seem like the positive effect metabolic surgery has on diabetes, hypertension and other disease is a recent discovery, the fact is that the use of surgery to treat OIMDs was being studied in the 1960s. As the evidence grew for bariatric surgery as a treatment for high cholesterol, high triglycerides and type-2 diabetes, the physiologic effects of the different operations began to be more closely examined. Due in part to the dramatic improvement in diabetes after gastric bypass, and the dramatic improvement in hyperlipidemia after intestinal bypass, the important role of hormones produced by the stomach and small intestine in the regulation of insulin, blood sugar and metabolism has become apparent.

In September 2008 the first World Congress on Interventional Therapies for Type-2 Diabetes was held in New York. The excitement at this meeting focused on evidence that surgery could be performed safely, on non-obese individuals, specifically to resolve diabetes without weight loss. Interest in these concepts resulted in studies on surgical procedures to treat type-2 diabetes being conducted throughout the world.

With an improved understanding of the role of the gastrointestinal tract in controlling cholesterol, triglycerides, insulin and our metabolism in general, the field of metabolic surgery is evolving. It is now very important for all physicians to understand modern metabolic surgery and its role as a treatment for OIMD, and sometimes as a cure.

References

Buchwald H, Varco RL. Ileal bypass in lowering high cholesterol levels. Surg Forum 1964; 15:289-291

Buchwald H, Varco RL. lleal bypass in patients with hypercholesterolemia and atherosclerosis: Preliminary report on therapeutic potential. JAMA 1966; 196:627-630

Pories WJ. Why does the gastric bypass control type 2 diabetes mellitus? Obes Surg. 1992;2:303–313

Forgacs S, Halmos T. Improvement of glucose tolerance in diabetics following gastrectomy [in German]. Z

Gastroenterol. 1973;11:293–296

Steven Grover S, et al. Preventing cardiovascular disease among Canadians: Is the treatment of hypertension or dyslipidemia cost-effective? Can J Cardiol 2008;24(12):891-898

Inabnet WB, et al. Early Outcomes of Bariatric Surgery in Patients with Metabolic Syndrome: An Analysis of the Bariatric Outcomes Longitudinal Database. J Am Coll Surg, 2012, 214, (4):556-557

Bariatric surgery in class 1 obesity (body mass index 30-35 kg/m2), ASMBS statements/guidelines, September 12, 2012

Buchwald H, et al. Bariatric Surgery, A Systematic Review and Meta-analysis. JAMA. 2004;292:1724-1737

Raul J. Rosenthal, M.D., F.A.C.S., F.A.S.M.B.S.*, for the International Sleeve Gastrectomy Expert Panel Consensus Statement. Surgery for Obesity and Related Diseases 8 (2012) 8 –19