bariatric surgery for obesity

Last edited 01/2024

The National Institute for Clinical Excellence has issued recommendations to the NHS on the use of gastric surgery for the treatment of morbid obesity

• NICE has recommended that surgery to aid weight loss should be available as a treatment option for people with morbid obesity provided that they meet all of the following criteria (1):
  
  

  • Referral regarding bariatric surgery:

    • bariatric surgery is a treatment option for people with obesity if all of the following criteria are fulfilled:
      • have a BMI of 40 kg/m2 or more, or between 35 kg/m2 and 39.9 kg/m2 with a significant health condition that could be improved if they lost weight (see box for examples)

        some conditions that can improve after bariatric surgery include: cardiovascular disease hypertension idiopathic intracranial hypertension non-alcoholic fatty liver disease with or without steatohepatitis obstructive sleep apnoea type 2 diabetes these examples are based on the evidence identified for this guideline and the list is not exhaustive.

      • and
      • agree to the necessary long-term follow up after surgery (for example, lifelong annual reviews)
        
    • consider referral for people of South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean family background using a lower BMI threshold (reduced by 2.5 kg/m2) thanto account for the fact that these groups are prone to central adiposity and their cardiometabolic risk occurs at a lower BMI
      
      
    • bariatric surgery - when to offer expedited assessment
      • offer an expedited assessment for bariatric surgery to people:
        • with a BMI of 35 kg/m2 or more who have recent-onset (diagnosed within the past 10 years) type 2 diabetes and
        • as long as they are also receiving, or will receive, assessment in a specialist weight management service
          
          
      • consider an expedited assessment for bariatric surgery for people:
        • with a BMI of 30 kg/m2 to 34.9 kg/m2 who have recent-onset (diagnosed within the past 10 years) type 2 diabetes and
        • who are also receiving, or will receive, assessment in a specialist weight management service
          
          
      • consider an expedited assessment for bariatric surgery for people of South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean family background using a lower BMI threshold (reduced by 2.5 kg/m2) to account for the fact that these groups are prone to central adiposity and their cardiometabolic risk occurs at a lower BMI

Types of bariatric surgery:

• bariatric surgery denotes any surgical procedure that is aimed at the reduction of excess weight
  • the conventional bariatric operations are divided as follows:
    
    
    • restrictive type [laparoscopic adjustable gastric banding (LAGB) or laparoscopic sleeve gastrectomy (LSG)]
      • LAGB - adjustable gastric band is a silicone belt with an inflatable balloon in the lining that is buckled into a closed ring around the upper stomach. A reservoir port is placed under the skin for adjustments to the stoma size
      • LSG consists of a 70% vertical gastric resection, which creates a long and narrow tubular gastric reservoir with no intestinal bypass component
        
        
    • malabsorptive type [bilio-pancreatic division with duodenal switch (BPD/DS)]
      • more extreme intestinal bypass along with some modest gastric reduction are the biliopancreatic diversion and the biliopancreatic diversion with duodenal switch operations, which are most often used for 'super' obese patients
      • biliopancreatic diversion combines a subtotal (2/3rds) distal gastrectomy and a very long Roux-en-Y anastomosis with a short common intestinal channel for nutrient absorption
      • biliopancreatic diversion with duodenal switch combines a 70% greater curve gastrectomy with a long intestinal bypass, where the duodenal stump is defunctionalized or 'switched' to a gastroileal anastomosis
        
        
    • combination type [roux-en-Y gastric bypass (RYGB) or mini gastric bypass

Notes:

• there is evidence (mainly from observational studies) that surgical treatment of obesity is more effective than non-surgical treatment for weight loss and control of comorbid conditions in patients with a BMI >= 40 kg/m^2 (3)
• a systematic review concluded that surgery is more effective than conventional management. Certain procedures produce greater weight loss, but data are limited (4)
• with respect to bariatric surgery in obese diabetic patients:
  • a study from Australia revealed that bariatric surgery was dominant over conventional therapy for lifetime management of type 2 diabetes in obese patients (5)
• a review states (6):
  • observational studies show that metabolic/bariatric surgery is associated with a lower incidence of cardiovascular events, cancer, and death
  • weight regain is a risk in a fraction of patients, and an association exists between metabolic/bariatric surgery and an increased risk of developing substance and alcohol use disorders, suicidal ideation/attempts, and accidental death
  • patients need lifelong follow-up to help to reduce the risk of these complications and other nutritional deficiencies.

Reference:

• 1. NICE (July 2023). Obesity guidance.
• 2. British Heart Foundation (February 2005). Obesity (4 of 4): Medical and Surgical Interventions.
• 3 Maggard MA et al. Meta-analysis: surgical treatment of obesity. Ann ntern Med 2005;142:547-59.
• 4. Colquitt JL, Picot J, Loveman E, Clegg AJ. Surgery for obesity. Cochrane Database Syst Rev. 2009 Apr 15;(2):CD003641.
• 5. Keating CL et al. Cost-effectiveness of surgically induced weight loss for the management of type 2 diabetes: modeled lifetime analysis.Diabetes Care. 2009 Apr;32(4):567-74
• 6. Courcoulas A P, Daigle C R, Arterburn D E. Long term outcomes of metabolic/bariatric surgery in adults BMJ 2023; 383 :e071027 doi:10.1136/bmj-2022-071027