Should Eligibility for Bariatric Surgery Be Expanded?
Article Outline
Obesity, defined as having a body mass index (BMI) ≥30, affects 30% of adults in the United States, of whom 5% are morbidly obese (BMI ≥ 40). Obesity predisposes to type 2 diabetes, hypertension, dyslipidemia, sleep apnea, atherosclerosis, nonalcoholic fatty liver disease, cancer, arthritis, and various other diseases. These conditions increase health care expenditures and may decrease longevity. Although heredity plays an important role in obesity, the current epidemic is attributed mostly to the consumption of energy-dense foods and sedentary lifestyle. Bariatric surgery is rapidly gaining popularity for the treatment of morbid obesity because currently available medications, namely, sibutramine and orlistat, are ineffective.1 Gastroplasty and adjustable gastric banding decrease weight by restricting the gastric reservoir, delaying emptying and inducing satiety. Roux-en-Y gastric bypass restricts the gastric capacity and decreases nutrient absorption. Guidelines for bariatric surgery stipulate that patients must have failed previous attempts at losing weight, be screened for medical and psychological morbidity, and emphasize a multispeciality approach before after surgery. Patients with BMI ≥ 40 or BMI ≥ 35 and coexisting medical conditions are eligible for bariatric surgery.2
Studies have consistently shown bariatric surgery to be more effective than medical management.1, 3 Dramatic improvements in diabetes, hypertension, hyperlipidemia, and sleep apnea have also been reported after gastric bypass surgery.1, 3 In fact, some have suggested that surgery is a cure for metabolic abnormalities associated with obesity.1, 3 Two recent studies demonstrated that bariatric surgery increases survival.4, 5 Sjöström et al4 conducted a prospective study in which obese patients who chose bariatric surgery were compared with those who opted for medical treatment. Over a 10-year period, weight loss was significantly greater (14%–25%) after bariatric surgery compared with 2% in control patients. Mortality was reduced by 29% in the bariatric surgery group. Adams et al5 showed in a retrospective study that gastric bypass surgery reduced all cause mortality by 40%. Mortality from diabetes, coronary artery disease, and cancer was reduced by gastric bypass surgery.5 Given the burgeoning obesity epidemic and associated diseases, these statistics coupled with advances in endoscopic surgery will lead advocates of bariatric surgery to suggest the time has come to relax the stringent eligibility criteria.
However, there are unresolved issues that call for caution in the expansion of bariatric surgery. The mortality rate associated with bariatric surgery is estimated at 0.1%–2%, but is greatly influenced by the experience of the surgeon and facility.1 Postoperative complications of bariatric surgery are common, and include bleeding, venous thromboembolism, anastomotic leaks, wound infections, incisional and internal hernias, stricture, and small bowel obstruction.1 The “dumping syndrome,” manifested by facial flushing, palpitations, dizziness, fatigue, and diarrhea, may occur in as many as 70% of gastric bypass patients. Malabsorption after gastric bypass results in deficiencies of iron, calcium, folate, and vitamin B12 that require monitoring and replacement. Hyperinsulinemic hypoglycemia is a worrisome complication of gastric bypass surgery.6 Neuroglycopenia in this condition may be refractory to medical treatment and require subtotal or total pancreatectomy to reduce insulin.6 Because post-gastric bypass hyperinsulinism is typified by diffuse hyperplasia of pancreatic islets, gut-derived trophic factors have been suggested as culprits.6 The lesson here is that by altering the anatomy of the gastrointestinal tract, gastric bypass may provoke abnormal cellular and neurohumoral responses with dire consequences.
Surgery is undoubtedly a viable option for some obese patients, but it cannot become a primary treatment for the vast majority of patients. The idea that obesity can be controlled through surgical manipulation of the gastrointestinal tract ignores the complexity of energy homeostasis. Fundamentally, energy imbalance culminating in obesity involves interactions among the gut, brain, adipose tissue, and endocrine system. Progress has been made over the past decade, but our knowledge of obesity is rudimentary. Peptic ulcer offers a lesson on how a paradigm shift in pathophysiology can radically change treatment. Likewise, a deeper understanding of the pathogenesis of obesity and associated diseases will aid in the development of effective drugs. Meanwhile, diet, exercise, and lifestyle modifications should remain the cornerstones of weight management for all. Medications or surgical therapy should be individualized based on objective assessments of benefits, risks, and cost.
References
- . Surgical treatment of obesity. Nat Clin Pract Endocrinol Metab. 2007;3:574–583
- Assessment and preparation of patients for bariatric surgery. Mayo Clin Proc. 2006;81(10 Suppl):S11–S17
- Meta-analysis: surgical treatment of obesity. Ann Intern Med. 2005;142:547–559
- Effects of bariatric surgery on mortality in Swedish obese subjects. N Engl J Med. 2007;357:741–752
- Long-term mortality after gastric bypass surgery. N Engl J Med. 2007;357:753–761
- Hyperinsulinemic hypoglycemia with nesidioblastosis after gastric-bypass surgery. N Engl J Med. 2005;353:249–254
PII: S0016-5085(07)02035-5
doi:10.1053/j.gastro.2007.11.022
© 2008 AGA Institute. Published by Elsevier Inc. All rights reserved.
