The American Society for Metabolic and Bariatric Surgery (ASMBS) and the International Federation for the Surgery of Obesity (IFSO) updated guidelines for bariatric surgery, marking a shift from the previous National Institute of Health (NIH) criteria set over 30 years ago. These updates aim to align patient eligibility and care standards with advancements in surgical techniques, patient safety, and new research findings on metabolic and bariatric surgery (MBS) outcomes.
This research paper, a collaborative effort between the American Society for Metabolic and Bariatric Surgery and the International Federation for the Surgery of Obesity and Metabolic Disorders, presents a comprehensive review of the indications for metabolic and bariatric surgery (MBS). Using systematic reviews and a Delphi survey of experts, the paper examines the evidence supporting MBS for various patient populations, including those with different BMIs, age groups, and co-morbidities. The authors analyse the efficacy and safety of MBS in these groups, considering aspects such as weight loss, complications, and resolution of obesity-related conditions. Overall, the paper provides a strong foundation for evidence-based decision-making regarding the use of MBS in clinical practice.
Why Update the Guidelines?
Since the original 1991 guidelines, bariatric surgery has evolved significantly:
• Introduction of less invasive techniques, such as sleeve gastrectomy
• Improved patient safety through accreditation and specialized MBS training
• Enhanced follow-up care, reducing adverse events and promoting lasting health improvements
The old NIH criteria, however, remained in use, limiting surgery access for certain patient groups who could benefit from modern bariatric options.
Key Changes in the Guidelines
1. Expanded Eligibility:
• Lower BMI Thresholds: MBS is now recommended for those with a BMI of 30-34.9 if they have Type 2 diabetes or another obesity-related medical condition.
• No Comorbidities Required for Higher BMI: Individuals with a BMI of 35-40 can now be considered for surgery even if they don’t have obesity-associated complications, provided they undergo a thorough multidisciplinary assessment.
2. Inclusion of the Asian Population:
• Given the increased metabolic risks at lower BMIs in Asian populations, the guidelines now recognize a BMI of 25 as a criterion for considering MBS in Asian patients.
3. Older Adults:
• There is no longer an upper age limit for eligibility, but a patient’s overall health, including frailty, should be assessed to balance surgery benefits against possible risks.
Supporting Evidence for Changes
The updated guidelines are supported by systematic reviews and expert consensus (Delphi surveys), covering:
• Comparative studies on MBS outcomes across different BMI ranges
• Evidence on remission rates for Type 2 diabetes, hypertension, and weight loss
• Nutritional and post-operative complications, indicating specific risks for hypoabsorptive procedures but also clear benefits for most surgery types
Outcomes of Bariatric Surgery According to the New Criteria
The findings emphasized consistent benefits across different surgical options (e.g., Roux-en-Y, sleeve gastrectomy) with weight loss outcomes meeting or exceeding expectations. The remission rates for Type 2 diabetes and hypertension post-surgery ranged widely, with studies reporting 33-100% and 28-100% remission, respectively.
Conclusion: Bariatric Surgery as a Key Treatment for Obesity-Related Conditions
These guidelines reflect an evolved understanding of obesity’s impact on health, positioning bariatric surgery as a preventative and therapeutic option for a broader patient population. While MBS remains a significant intervention, these guidelines ensure it’s more accessible for patients who can gain long-term health benefits.
For a detailed read, refer to the original study in Obesity Surgery here.
Updated Guidelines on Bariatric Surgery: A Comprehensive Overview