IFSO ASMBS guidelines




ASMBS/IFSO Guidelines on Indications for Metabolic and Bariatric Surgery – 2022, published simultaneously in the journals, Surgery for Obesity and Related Diseases (SOARD) and Obesity Surgery, were developed to replace the 1991 NIH Consensus Statement on Bariatric Surgery, which provided guidance on patient selection, weight-loss procedures and obesity and has not changed since its publication more than 30 years ago.

Major Differences Between 1991 NIH Guidelines and ASMBS/IFSO Guidelines 2022

• Metabolic and Bariatric Surgery (MBS) recommended for individuals with BMI >35 kg/m2, regardless of presence or absence of comorbidities and should be considered for individuals with metabolic disease and BMI 30-34.9 kg/m2 who do not achieve substantial or durable weight loss or comorbidity improvement using nonsurgical methods.

• BMI thresholds should be adjusted in the Asian population such that BMI >25 kg/m2 suggests clinical obesity, and individuals with BMI >27.5 kg/m2 should be offered MBS

• Appropriately selected children/adolescents should be considered for MBS.

• Data, including randomized clinical trials, real-world studies and patient outcomes spanning more than 30 years supports the safety, effectiveness and durability of MBS and its superiority to nonsurgical methods.

• Metabolic surgery, not mentioned in 1991, takes on new significance and prominence for patients with lower BMIs and type 2 diabetes.

Summary of Recommendations in ASMBS/IFSO Guidelines 2022

• Long-term data consistently demonstrate the safety, efficacy, and durability of MBS in the treatment of clinically severe obesity and its comorbidities, with decreased mortality compared with nonoperative treatments.

• MBS is recommended for individuals with BMI >35 kg/m2, regardless of presence, absence, or severity of comorbidities and for patients with type 2 diabetes and BMI>30 kg/m2.

• MBS should be considered in individuals with BMI 30 to 34.9 who do not achieve substantial or durable weight loss or comorbidity improvement using nonsurgical methods.

• Obesity definitions using BMI thresholds do not apply similarly to all populations.

o Clinical obesity in the Asian population is recognized in individuals with BMI >25 kg/m2.

o Access to MBS should not be denied solely based on traditional BMI risk zones.

• Older adults should be considered for MBS after careful assessment of comorbidities and frailty.

• Carefully selected individuals considered higher risk for general surgery may benefit from MBS.

• Children/adolescents with a BMI >120% of the 95th percentile and major comorbidity, or a BMI >140% of the 95th percentile should be considered for MBS after evaluation by a multidisciplinary team in a specialty center.

• MBS is an effective treatment of clinically severe obesity in patients who need other specialty surgery, such as joint arthroplasty, abdominal wall hernia repair, or organ transplantation.

• Consultation with a multidisciplinary team can help manage the patient’s modifiable risk factors with a goal of reducing risk of perioperative complications and improving outcomes.

• Severe obesity is a chronic disease requiring long-term management after primary MBS, which may include revisional surgery or other adjuvant therapy to achieve desired treatment effect.

Worldwide Obesity
• Globally, more than 650 million adults had obesity in 2016, which is about 13% of the world’s adult population. CDC reports over 42% of Americans have obesity, the highest incidence ever recorded in the U.S.1

Premature Death and Life-threatening Diseases Linked to Obesity
• Obesity is linked to more than 40 other diseases including type 2 diabetes, heart disease, stroke, and certain types of cancer, some of the leading causes of preventable and premature death.2,3

Treatment with Metabolic and Bariatric Surgery
• Metabolic/bariatric surgery is the most effective and durable treatment for severe obesity leading to significant weight loss and the improvement, prevention or resolution of many obesity related diseases including type 2 diabetes, heart disease, stroke and certain cancers.4,5

o Studies show bariatric surgery may reduce a patient’s risk of premature death by 30-50%.6,7

o Patients may lose as much as 60% of excess weight six months after surgery and 77% of excess weight as early as 12 months after surgery.8

o Overall, bariatric surgery has complication and mortality rates (4% and 0.1%, respectively) comparable to common surgeries including gallbladder surgery, appendectomy and knee replacement.9

Metabolic and Bariatric Surgery is Significantly Underutilized
• According to ASMBS and IFSO, only between 1% and 2% of the world’s eligible population receive weight loss surgery in any given year — sleeve gastrectomy and laparoscopic gastric bypass account for 90% of procedures.
Metabolic Surgery vs. Medical Therapy

• Randomized clinical trials demonstrate metabolic surgery is more effective than medical and/or lifestyle interventions in producing diabetes remission, glycemic control, and weight loss.

o Five-year randomized study showed metabolic surgery plus intensive medical therapy were more effective than intensive medical therapy alone for achieving and maintaining glycemic control, weight reduction, medication reduction, and improvements in lipid levels in patients with uncontrolled type 2 diabetes (mean BMI 37).

o Diabetes remission rates at years one, three and five were about 40% compared to 12%, 5% and 5% seen with medical therapy alone.

International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO)

• The International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) is a Federation composed of national associations of bariatric surgeons and integrated health professionals from all over the world.

o 72 official member societies and more than 10,000 members.

o Brings together surgeons and integrated health professionals, such as nurses, practitioners, dieticians, nutritionists, psychologists, internists and anesthesiologists involved in the treatment of obesity.

American Society for Metabolic and Bariatric Surgery (ASMBS)

• Founded in 1983, the largest scientific organization in the U.S. dedicated to metabolic and bariatric surgery.

• Seeks to improve public health and well-being by lessening burden of obesity and related diseases.

• Has more than 4,000 members including surgeons and integrated healthcare professionals practicing in the field of metabolic and bariatric surgery.

2 Kaplan L. J Gastrointest Surg. 2003;7(4):proceeding;443_451)
3 “Adult Obesity Facts | Overweight & Obesity | CDC.” Centers for Disease Control and Prevention, 5 Mar. 2018, Accessed 16 Apr. 2018.
4 Weiner, R. A., et al. (2010). Indications and principles of metabolic surgery. U.S. National Library of Medicine. 81(4) pp.379-394. Accessed from:
5 The Effectiveness and Risks of Bariatric Surgery: An Updated Systematic Review and Meta-analysis, 2003-2012 Accessed from:
6 Sjöström. L., et al. (2007). Effects of bariatric surgery on mortality in Swedish obese subjects. New England Journal of Medicine. 357 pp. 741-752 Accessed October 2013 from
7 Adams, T. D., et al. (2007). Long-term mortality after gastric bypass surgery. New England Journal of Medicine. 357 pp. 753-761. Accessed from:
8 Wittgrove, A. C., et al. (2000). Laparoscopic gastric bypass, roux-en-y: 500 patients: technique and results, with 3-60 month follow-up. Obesity Surgery. 10(3) pp. 233-239. Accessed from
9 Aminian, A., et al. (2015). How safe is metabolic/diabetes surgery? Diabetes Obesity Metabolism. Feb;17(2):198-201. doi: 10.1111/dom.12405 Accessed from



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