Bariatric Surgery

• Most effective method to reduce and maintain weight in severely obese patients
• Associated with average weight losses of between 16-35% of up to 8 years depending on type of surgical procedure
  • Laparoscopic technique is the first treatment of choice
• Based on long-term data, surgery has been shown to reduce overall mortality over a 15-year period compared to conservative medical treatment
• May fail in up to 35% of patients after 5 years in patients with BMI >35
• According to the 2016 American Association of Clinical Endocrinologists (AACE) and American College of Endocrinology (ACE) guidelines, it is indicated in patients with BMI ≥40 or BMI 35-39.9 with comorbidities in whom weight loss through surgery is expected to improve the disorder (eg diabetes mellitus and other metabolic disorders, cardiovascular disease, severe joint disease, and obesity-related severe psychological disorders)
• Should be considered in patients with BMI 30-34.9 and poorly controlled T2DM despite optimal medical treatment  
• May be considered in patients with BMI 30-34.9 who have not achieved significant weight loss despite optimal medical and behavioral treatment
• The International Federation for the Surgery of Obesity and Metabolic Disorders - Asia Pacific Chapter (IFSO-APC) consensus statements in 2011 recommend bariatric surgery in the following Asian patients with:
  • BMI ≥35 with or without comorbidities
  • BMI ≥30 inadequately controlled by lifestyle changes or medical therapy for the treatment of T2DM or metabolic syndrome
  • BMI ≥27.5 as non-primary treatment alternative for inadequately controlled T2DM or metabolic syndrome
• Contraindications:
  
  • Current alcohol abuse
  • Unstable psychological conditions
  • Esophageal dysmotility, inflammatory bowel disease, chronic pancreatitis, bile duct pathology
  • Portal hypertension, active malignancy
  • Regular use of NSAIDs or corticosteroids
  • History of gastric cancer
  • Vegetarians

• Medical follow-up at 1, 3, 6 and 12 months then annually is advised
• Complications may include dumping syndrome, hypoglycemia, malnutrition, regain of weight, or revisional surgery
• Long-term mineral and multivitamin supplementation is recommended post-surgery
• Restrictive Procedure
  
  • Limits intake of food by creating small gastric pouch causing feeling of fullness
  • Estimated weight loss of 30% in 1 year
  • Eg vertical sleeve gastrectomy, laparoscopic adjustable gastric band, intragastric balloon (IGB)
• Malabsorptive Procedure
  • Limits absorption of macronutrients
  • Eg biliopancreatic diversion, duodenal switch, gastric bypass
  • Gastric bypass is the gold standard in bariatric surgical operation as it produced massive weight loss in obese patients
    • Roux-en-Y gastric bypass combines both restrictive and malabsorptive techniques