Bariatric and Metabolic Surgery

• Most effective method to reduce and maintain weight in severely obese patients
• Associated with average weight losses of between 16-35% in up to 8 years depending on type of surgical procedure
  • Laparoscopic approach 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
  • Surgery improves ORCs and quality of life and decreases CV mortality and morbidity
• Metabolic surgery should be done in high-volume centers with well-informed and experienced multidisciplinary teams; strict selection criteria should be applied 
• May have partial weight regain in up to 35% of patients after 5 years in patients with BMI >35 kg/m²
• 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 kg/m² or BMI 35-39.9 kg/m² with comorbidities in whom weight loss through surgery is expected to improve the disorder (eg DM and other metabolic disorders, CVD, severe joint disease, and obesity-related severe psychological disorders)
• The 2nd Diabetes Surgery Summit (DSS-II):
  • Recommends metabolic surgery for the treatment of T2DM Asian patients with class III obesity (BMI ≥37.5 kg/m²) and class II obesity (BMI 32.5-37.4 kg/m²) when optimal lifestyle and medical treatment are inadequate to control hyperglycemia
  • Considers metabolic surgery for patients with class II obesity with adequate glycemic control and class I obesity (BMI 27.5-32.4 kg/m²) with poor glycemic control despite optimal lifestyle and medical treatment (including injectable medications and insulin)
• 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 kg/m² with or without comorbidities
  • BMI ≥30 kg/m² inadequately controlled by lifestyle changes or medical therapy for the treatment of T2DM or metabolic syndrome
  • BMI ≥27.5 kg/m² as non-primary treatment alternative for inadequately controlled T2DM or metabolic syndrome
• Contraindications:
  
  • Current alcohol/substance abuse
  • Unstable psychological conditions
  • Esophageal dysmotility, inflammatory bowel disease, chronic pancreatitis, bile duct pathology
  • Portal hypertension, active malignancy
  • Regular use of NSAIDs
  • History of gastric cancer
  • Relative contraindication includes inability to comply with postoperative nutritional changes or follow-ups
• Commonly performed bariatric surgery procedures in Asia include sleeve gastrectomy, Roux-en-Y gastric bypass (RYGB), adjustable gastric band (AGB) and biliopancreatic diversion with duodenal switch (BPD-DS) 
• Endoscopic bariatric procedures include intragastric balloon and endoscopic sleeve gastroplasty (ESG); ESG results in about 15-20% weight loss at 12-24 months when combined with lifestyle modification
• Medical follow-up at 1, 3, 6 and 12 months then annually is advised
• Complications may include dumping syndrome, hypoglycemia, malnutrition including mineral and vitamin deficiencies, anemia, osteoporosis, regain of weight, or need for revisional surgery
• Long-term lifestyle support and micronutrient and nutritional status monitoring (eg mineral and multivitamin supplementation) are mandatory post-surgery