Obesity & Metabolic Disorders

Obesity and obesity-related metabolic disorders impose a tremendous burden on the healthcare system in the United States. In the US, over 75 million adults are obese, defined as a body mass index (BMI) > 30.

Of the obese population in the US:

  • 20%, or 15 million, are diagnosed with type-2 diabetes
  • Over 33%, or 25 million, have hypertension.

These diseases are chronic in nature, and require long-term therapies for successful treatment.

It is estimated that obesity and obesity-related disorders cost the US healthcare system over $150 billion per year. Diet, exercise, and pharmaceutical therapies are the primary non-surgical treatments for obesity today. Americans spend more than $60 billion annually on weight loss products and non-surgical treatments. However, these programs have a failure rate of up to 95 percent at five years. Studies indicate that people, who complete non-surgical weight-loss programs and lose approximately 10 percent of their body weight, gain one third of it back within one year and almost all of it back within five years. There is no evidence to suggest that existing non-surgical treatments will achieve significant and sustained weight loss in the severe or morbid obese patient.

NIH guidelines currently stipulate that surgical intervention is indicated only for those with a BMI of 40 or more, or BMI 35 with significant co-morbidities. Bariatric surgery facilitates weight loss by changing the way your body consumes, digests, and absorbs food. There are two primary types of bariatric surgery: 1) restrictive and 2) combined (restrictive and malabsorptive).

Restrictive surgery uses bands or staples to restrict the amount of food intake and causes an early and prolonged sensation of satiety. The bands or staples are surgically placed to section off a portion of the stomach and create a pouch. A small outlet, or stoma, may be created at the bottom of the pouch. Since the outlet is small, food fills the pouch and patients feel full after the consumption of small meals.

In a combined procedure (restrictive and malabsorptive), such as the Roux-en-Y gastric bypass, a restriction is created by stapling the stomach and forming a small pouch. In addition, the small bowel is divided and connected to the pouch. The remaining stomach and proximal duodenum is then connected to the jejunum. Food passes from the esophagus into the pouch and then directly into the jejunum. Bypassing the stomach and part of the small intestine suppresses appetite and limits absorption of fats.

Restrictive
(Gastric Banding)
Combined
(Roux-en-Y Gastric Bypass)

In addition to weight loss, bariatric surgical procedures have shown to be very effective in treating metabolic disorders. According to "Bariatric Surgery, A Systematic Review and Meta-Analysis" published in JAMA, patients who had gastric bypass surgery, had an average excess weight loss of 68%, while those who had gastric banding had an average excess weight loss of 48%. In addition, both procedures demonstrated a significant reduction in obesity-related metabolic co-morbidities:

Percent of Patients with
Co-morbidity Resolution by Procedure

  Gastric Bypass Gastric Banding
Type-2 Diabetes 84% 48%
Hypertension 75% 38%
Hyperlipidemia 94% 71%
Bariatric surgery: A Systematic Review and Meta-analysis. JAMA 2004;292:1724–37

While the mechanisms of action for each procedure are still being studied, a combined restrictive and mal-absorptive procedure, like the gastric bypass, showed a higher degree of weight loss and co-morbidity resolution. Many researchers point to the hormonal effects related to bypassing the stomach and intestine to explain the more pronounced benefits associated with combined procedures.

Over 250,000 bariatric surgeries are performed each year in the United States, and while this number has grown dramatically, only a small fraction of the eligible population is currently seeking treatment through surgery. Safety, cost, and perception are all factors that limit the wide-spread adoption of surgical treatment.

The advent of effective non-surgical therapies has the potential to revolutionize the treatment paradigm. Millions of patients, who currently don't seek treatment or are marginally helped through conventional therapies, may be able to gain resolution of their obesity and obesity-related co-morbidities with these new therapies.

Obesity &
Metabolic
Disorders