What are the indications for bariatric (weight loss) surgery?

From the Guidelines

Bariatric surgery is indicated for individuals with a body mass index (BMI) of 35 kg/m² or greater, or a BMI of 30-34.9 kg/m² with concurrent metabolic disease, such as type 2 diabetes, as stated in the most recent guidelines 1. The primary goal of bariatric surgery is to achieve significant weight loss and improve or resolve obesity-related comorbidities, thereby reducing morbidity, mortality, and improving quality of life.

Key Indications for Bariatric Surgery

• A BMI of 40 kg/m² or greater (class III obesity)
• A BMI of 35-39.9 kg/m² (class II obesity) with at least one obesity-related comorbidity
• A BMI of 30-34.9 kg/m² with poorly controlled type 2 diabetes or metabolic syndrome, particularly in Asian populations

Important Considerations

• Patients should have attempted weight loss through diet, exercise, and behavioral changes before considering surgery
• Patients should be psychologically stable and committed to long-term lifestyle changes and follow-up care
• Contraindications include untreated major depression or psychosis, active substance abuse, inability to comply with nutritional requirements, or severe cardiac disease that makes surgery too risky

Surgical Procedures

• Laparoscopic sleeve gastrectomy (LSG) and Roux-en-Y gastric bypass (RYGB) are the most common procedures, accounting for more than 90% of all surgeries 1
• Expected 12-month weight loss is approximately 25% after LSG and approximately 30% after RYGB, with sustained weight loss at 5 years 1

Risks and Complications

• Early complications include anastomotic leaks, stenosis, postoperative bleeding, and venous thromboembolic events 1
• Late complications include internal hernia and marginal ulceration 1
• Nutritional deficiencies are a potential risk, and pre- and post-surgical screening and supplementation for micronutrients are recommended 1

From the Research

Indications for Bariatric Surgery

Bariatric surgery is recommended for individuals with a Body Mass Index (BMI) over 40 kg/m2 or with a BMI between 35 and 40 kg/m2 with obesity-related comorbidities 2, 3, 4, 5. The following are some of the key indications for bariatric surgery:

• BMI of 40 kg/m2 or higher 2, 3, 4, 5
• BMI between 35 and 40 kg/m2 with obesity-related comorbidities such as type 2 diabetes, hypertension, dyslipidemia, and sleep apnea 2, 3, 4, 5
• Type 2 diabetes with a BMI between 30 and 35 kg/m2, if hyperglycemia is inadequately controlled despite optimal medical treatment 3
• Severe obesity with related diseases, such as dyslipidemia, sleep apnea, and chronic joint pain 5

Special Considerations

Some studies suggest that bariatric surgery can be beneficial for patients with a BMI less than 35 kg/m2, particularly those with severe comorbidities 6. However, the evidence for this is limited, and more research is needed to fully understand the benefits and risks of bariatric surgery in this population.

Comorbidities

Bariatric surgery has been shown to improve or resolve a range of comorbidities, including:

• Type 2 diabetes 2, 3, 6
• Hypertension 2, 3, 6
• Dyslipidemia 2, 3, 6
• Sleep apnea 2, 3, 6
• Osteoarthritis 6

Surgical Procedures

Several surgical procedures are available for bariatric surgery, including:

• Laparoscopic adjustable gastric banding (LAGB) 2
• Roux-en-Y gastric bypass (RYGB) 2, 3, 5
• Sleeve gastrectomy (SG) 2, 3, 6
• Bilio-pancreatic diversion (BPD) 2
• Duodenal switch (DS) 2