Affecting more than one-third of adults in the US, obesity remains a pressing health challenge for both providers and patients, conferring significant risk for comorbidities such as type 2 diabetes, obstructive sleep apnea, and cardiovascular disease. While lifestyle modifications and medical therapies, including anti-obesity medications (AOM), can be effective for some, they often fall short in achieving sustained weight loss and improved health for many patients. Bariatric surgery emerges as a crucial tool when conservative measures are insufficient, offering significant, long-term benefits for those with severe obesity.
This article explores current clinical practice guidance documents for managing bariatric surgery patients, comparing and highlighting recommendations regarding patient selection, procedural choices, and perioperative complications from various leading medical societies. In analyzing the evolving recommendations on the use of surgical interventions in the comprehensive treatment of obesity, this Guidelines Side-By-Side aims to equip healthcare providers with the insights needed to optimize bariatric surgery patient care through evidence-based, personalized treatment strategies.

Titles of Comparison:

  • 2024 Obesity Algorithm – Management of the Bariatric Surgery Patient
    • Published by the Obesity Medicine Association (OMA) on February 2024.
    • Objective: Provides ungraded recommendations and guidance for the management of bariatric surgery patients, including nutrient considerations, as a part of the 2024 Obesity Algorithm.
    • Target Population: Adults with indications for metabolic and bariatric surgery
    • Methodology: Ungraded key takeaway recommendations
    • Graded Strength of Recommendations: No
    • Graded Level of Evidence: No
    • Systematic Review Conducted: Not stated
    • Literature Review Conducted: Yes
    • Internal Review Conducted: Yes
    • External Review Conducted: Not stated
    • COIs & Funding Source(s) Disclosed: Yes
    • Pocket Guide | Full-text
  • Perioperative Nutritional, Metabolic, and Nonsurgical Support of the Bariatric Surgery Patient
    • Published by the American Association of Clinical Endocrinologists (AACE), American Society for Metabolic and Bariatric Surgery (ASMBS), American Society of Anesthesiologists (ASA), The Obesity Society (TOS), Obesity Medicine Association (OMA) on November 2019.
    • Objective: This 2019 clinical practice guideline (CPG) update provides revised clinical management recommendations that incorporate evidence from 2013 to the present, and identifies patient candidates for bariatric procedures, discusses which types of bariatric procedures should be offered, outlines management of patients before procedures, and recommends how to optimize patient care during and after procedures. 
    • Target Population: Adults with indications for metabolic and bariatric surgery
    • Methodology: AACE Protocol for Standardized Production of Clinical Practice Guidelines, Algorithms, and Checklists – 2017 Update
    • Graded Strength of Recommendations: Yes (A: Strong, B: Intermediate, C: Weak, D: No conclusive evidence and/or expert opinion)
    • Graded Level of Evidence: Yes (H: High, H-I: Intermediate High, I: Intermediate, L-I: Low-Intermediate, L: Low, L-E: Low/Expert Opinion)
    • Systematic Review Conducted: Yes
    • Literature Review Conducted: Yes
    • Internal Review Conducted: Yes
    • External Review Conducted: Not stated
    • COIs & Funding Source(s) Disclosed: Yes
    • Pocket Guide | Full-text
  • Indications for Metabolic and Bariatric Surgery
    • Published by the American Society for Metabolic and Bariatric Surgery (ASMBS), International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) on October 2022.
    • Objective: This joint statement is an update to the 1991 National Institutes of Health (NIH) consensus statement, which sought to address “the surgical treatments for severe obesity and the criteria for selection, the efficacy and risks of surgical treatments for severe obesity, and the need for future research on and epidemiological evaluation of these therapies,” and included specific recommendations for practice. 
    • Target Population: Adult and pediatric patients with indications for metabolic and bariatric surgery
    • Methodology: Not stated
    • Graded Strength of Recommendations: No
    • Graded Level of Evidence: No
    • Systematic Review Conducted: Not stated
    • Literature Review Conducted: Yes
    • Internal Review Conducted: Not stated
    • External Review Conducted: Not stated
    • COIs & Funding Source(s) Disclosed: Not stated
    • Pocket Guide | Full-text

Comparison Content:

AACE/ASMBS/ASA/TOS/OMA (2019):
Perioperative Nutritional, Metabolic, and Nonsurgical Support of the Bariatric Surgery Patient
ASMBS/IFSO (2022):
Indications for Metabolic and Bariatric Surgery

OMA (2024): 
Obesity Algorithm: Management of the Bariatric Surgery Patient
Potential Surgical Candidates
• BMI ≥ 40 without coexisting medical problems and for whom bariatric procedures would not be associated with excessive risk are eligible for a bariatric procedure.

• BMI ≥ 35 and one or more severe obesity- related complications (ORCs) remediable by weight loss, including T2DM, high risk for T2DM, poorly controlled HTN, NAFLD/NASH, OSA, OA of the knee or hip, and/or urinary stress incontinence
– May also be considered for select patients with complications related to obesity hypoventilation syndrome, Pickwinian syndrome, IIHTN, GERD, severe venous stasis disease, impaired mobility due to obesity, and/or considerably impaired quality of life

• BMI 30 to 34.9 and T2D with inadequate glycemic control despite optimal lifestyle and medical therapy-

• BMI criterion for bariatric procedures should be adjusted for ethnicity (e.g., 18.5 to 22.9 is normal range, 23 to 24.9 overweight, and ≥ 25 considered obesity for Asians)














































• Medical weight loss is considered to have greater durability in individuals with BMI less than 35 than individuals with BMI greater than 35, and thus it is recommended that a trial of nonsurgical therapy is attempted before considering surgical treatment. 

• MBS is recommended for individuals with BMI ≥35, regardless of presence, absence, or severity of comorbidities.

• MBS is recommended in patients with T2D and BMI ≥30.

• MBS should be considered in individuals with BMI of 30–34.9 who do not achieve substantial or durable weight loss or co-morbidity improvement using nonsurgical methods.

• Clinical obesity in the Asian population is recognized in individuals with BMI >25
– Access to MBS should not be denied solely based on traditional BMI risk zones.

• There is no upper patient-age limit to MBS. 
– Older individuals who could benefit from MBS should be considered for surgery after careful assessment of co-morbidities and frailty.
– Frailty, rather than age alone, is independently associated with higher rates of postoperative complications following MBS

• Children and adolescents with BMI >120% of the 95th percentile and a 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 transplant.		• BMI ≥35 with one or more adverse health consequences due to obesity (based on 1991 NIH Consensus Development Panel)

• BMI ≥40 (based on 1991 NIH Consensus Development Panel)
BMI ≥30 with type 2

• DM (based on 2022 ASMBS Guidelines) Note: BMI ≥25 in Asian individuals

• BMI ≥30 without substantial or durable weight loss or co-morbidity improvement using nonsurgical methods (based on 2022 ASMBS Guidelines) 
– Note: BMI ≥25 in Asian individuals

• BMI ≥40 (based on 2022 ASMBS Guidelines) 
– Note: BMI ≥27.5 in Asian individuals







































Considerations by Surgical Procedure
Roux-en-Y Gastric BypassLAGB, laparoscopic sleeve gastrectomy (LSG), laparoscopic Roux-en-Y gastric bypass (LRYGB), and laparoscopic biliopancreatic diversion without/with duodenal switch (BPD/DS), or related procedures should be considered as primary bariatric and metabolic procedures performed in patients requiring weight loss and/or amelioration of obesity-related complications (ORCs).

Diabetes:
• Close attention to dosing of diabetes medication is recommended for those having had SG, RYGB, or BPD/DS, since these patients generally have dosing reduced in the early postoperative period

Pregnancy:
• Candidates for bariatric procedures should avoid pregnancy pre procedure and for 12 to 18 months post procedure. Patients undergoing Roux-en-Y gastric bypass (RYGB) or another malabsorptive procedure should be counseled about non-oral contraceptive therapies

Cholecystitis & Choledocholithiasis:
• RUQ pain should be evaluated for cholecystitis
– SG, RYGB, or BPD/DS are at increased risk for cholelithiasis due to rapid weight loss & should be treated with PO ursodeoxycholic acid 300mg BID following RYGB.
– Asymptomatic patients with known gallstones and a history of RYGB or BPD/DS, prophylactic cholecystectomy may be considered to avoid choledocholithiasis

Psychosocial considerations:
• Following RYGB and SG, high-risk groups should eliminate alcohol consumption due to impaired alcohol metabolism and risk of alcohol-use disorder postoperatively
• Adolescents with severe obesity undergoing RYGB have significantly greater weight loss and improvement in cardiovascular risk factors and T2D compared to adolescents undergoing medical management.
– Improvement in HTN and dyslipidemia has been demonstrated up to 8 years after surge.
-Benefits of RYGB on T2D and hypertension are greater in adolescents than adults

• Medical therapy with RYGB or sleeve gastrectomy were shown to be superior to medical therapy alone in the long-term treatment of T2D

















• Expected excess body weight loss: 60-75% 

• Optimally suited for patients with higher BMI, GERD, T2DM

• Increased risk of malabsorptive complications over sleeve






























Laparoscopic Adjustable Gastric Banding (LAGB)LAGB, laparoscopic sleeve gastrectomy (LSG), laparoscopic Roux-en-Y gastric bypass (LRYGB), and laparoscopic biliopancreatic diversion without/with duodenal switch (BPD/DS), or related procedures should be considered as primary bariatric and metabolic procedures performed in patients requiring weight loss and/or amelioration of obesity-related complications ORCs.

Diabetes:
• Dosing of diabetes medications in the post-op period for those having had LAGB require significant weight loss before dosing must be reduced.

• Pregnancy: Patients who become pregnant post LAGB should have band adjustments as necessary for appropriate weight gain for fetal health.

• Post-op monitoring:
– Significant weight regain or failure to lose weight after a should prompt a comprehensive evaluation that includes assessing for inadequate band restriction 
– Persistent vomiting, regurgitation, and upper-GI obstruction after LAGB should be treated with immediate removal of fluid from the adjustable band. 
• Poorer outcomes after total joint arthroplasty (TKA) have been associated with obesity, but those who received AGB had ~30% who were able to decline the TKA due to joint symptom improvement following bariatric surgery & weight loss




















• Expected excess body weight loss: 30–50%

• Optimally suited for patients with lower BMI, No metabolic disease

• Limited efficacy: any metabolic benefits achieved are dependent on weight loss

















Biliopancreatic Diversion with Duodenal Switch (BPD/DS)LAGB, laparoscopic sleeve gastrectomy (LSG), laparoscopic Roux-en-Y gastric bypass (LRYGB), and laparoscopic biliopancreatic diversion without/with duodenal switch (BPD/DS), or related procedures should be considered as primary bariatric and metabolic procedures performed in patients requiring weight loss and/or amelioration of obesity-related complications ORCs.

Diabetes:
• Close attention to dosing of diabetes medication is recommended for those having had SG, RYGB, or BPD/DS, since these patients generally have dosing reduced in the early postoperative period

Cholecystitis & Choledocholithiasis:
• RUQ pain should be evaluated for cholecystitis, – SG, RYGB, or BPD/DS are at increased risk for cholelithiasis due to rapid weight loss & should be treated with PO ursodeoxycholic acid 300mg BID following BPD/DS
– Asymptomatic patients with known gallstones and a history of RYGB or BPD/DS, prophylactic cholecystectomy may be considered to avoid choledocholithiasis		• Not discussed

























• Expected excess body weight loss: 70–80%

• Optimally suited for patients with higher BMI, T2DM

• While biliopancreatic diversion with duodenal switch may result in the greatest amount of weight loss, it is a procedure that has a high rate of multiple post-procedure vitamin and mineral deficiencies









Loop Duodenal SwitchLAGB, laparoscopic sleeve gastrectomy (LSG), laparoscopic Roux-en-Y gastric bypass (LRYGB), and laparoscopic biliopancreatic diversion without or with duodenal switch (BPD/DS), or related procedures should be considered as primary bariatric and metabolic procedures performed in patients requiring weight loss and/or amelioration of obesity-related complications ORCs.• Not discussed







• Expected excess body weight loss: 70–80%

• Optimally suited for patients with higher BMI, T2DM

• Long-term data not available
Endoscopic Sleeve Gastroplasty (ESG)Pre-op evaluation:
• The use of preoperative endoscopy may be considered in all patients being evaluated for sleeve gastrectomy (SG)
• Clinically significant gastrointestinal (GI) symptoms should be evaluated pre-op with imaging studies, upper GI series, or endoscopy
– The use of pre-op endoscopy may be considered in all patients being evaluated for sleeve gastrectomy

Diabetes:
• Close attention to dosing of diabetes medication is recommended for those having had SG, RYGB, or BPD/DS, since these patients generally have dosing reduced in the early postoperative period

Cholecystitis & Choledocholithiasis:
• RUQ pain should be evaluated for cholecystitis
– SG, RYGB, or BPD/DS are at increased risk for cholelithiasis due to rapid weight loss & should be treated with PO ursodeoxycholic acid 500mg once a day following a sleeve gastrectomy

Post-op considerations:
• Patients with de novo gastroesophageal reflux and severe symptoms after SG should be treated with proton-pump inhibitor therapy		• Medical therapy with RYGB or sleeve gastrectomy were shown to be superior to medical therapy alone in the long-term treatment of T2D






















• Indication: BMI 30-50

• Efficacy: 16% total body weight loss and 60% excess weight loss for up to 1–2 years
– Improvement of at least 1 weight-related chronic disease in 80% of individuals


















Vertical Sleeve Gastrectomy (VSG)LAGB, laparoscopic sleeve gastrectomy (LSG), laparoscopic Roux-en-Y gastric bypass (LRYGB), and laparoscopic biliopancreatic diversion without/with duodenal switch (BPD/DS), or related procedures should be considered as primary bariatric and metabolic procedures performed in patients requiring weight loss and/or amelioration of obesity-related complications ORCs.

Pre-op evaluation:
• The use of preoperative endoscopy may be considered in all patients being evaluated for sleeve gastrectomy (SG)

Post-op considerations:
• Patients with de novo gastroesophageal reflux and severe symptoms after SG should be treated with proton-pump inhibitor therapy
Diabetes: Close attention to dosing of diabetes medication is recommended for those having had SG, RYGB, or BPD/DS, since these patients generally have dosing reduced in the early postoperative period

Cholecystitis & Choledocolithtiasis:
• RUQ pain should be evaluated for cholecystitis
– SG, RYGB, or BPD/DS are at increased risk for cholelithiasis due to rapid weight loss & should be treated with PO ursodeoxycholic acid 500mg once a day following a sleeve gastrectomy

Psychosocial considerations:
• Following RYGB and SG, high-risk groups should eliminate alcohol consumption due to impaired alcohol metabolism and risk of alcohol-use disorder postoperatively		• The VBG (vertical banded gastroplasty) is of historical interest and no longer performed, VSG/ESG not explicitly discussed































• Expected excess body weight loss: 50–70% 

• Optimally suited for patients with metabolic disease

• Can worsen GERD & Barrett’s esophagus 



























Key Takeaways:

Indications for bariatric surgery by BMI:

  • Recommended candidates for bariatric & metabolic surgery include patients with:
    • BMI > 40 recommended by all societies
    • BMI > 35 with:
      • One or more associated obesity-related complications recommended by OMA and AACE
      • AMSBS recommends BMI ≥35, regardless of presence, absence, or severity of comorbidities.
    • BMI >30 with:
      • AACE: BMI 30 to 34.9 and T2D with inadequate glycemic control despite optimal lifestyle and medical therapy
      • OMA & ASMBS recommend in patients with T2D and BMI ≥30, as well as BMI >30 who did not show substantial or durable weight loss or co-morbidity improvement using nonsurgical methods
    • Ethnicity-related BMI considerations:
      • In Asian patient populations, BMI ≥25 kg/m2 suggests clinical obesity, and individuals with BMI ≥27.5 kg/m2 should be offered MBS recommended by all societies
    • Special patient population considerations:
      • Only discussed by ASMBS/IFSO, recommend no upper age limit for bariatric and metabolic surgery, but fragility is independently associated with higher rates of postoperative complications 
      • Only discussed by ASMBS/IFSO, children and adolescents with BMI >120% of the 95th percentile and a major comorbidity, or a BMI >140% of the 95th percentile, should be considered for MBS

Recommendations and considerations by procedure:

  • Roux-En-Y Gastric Bypass (RYGB):
    • Recommended by AACE to be considered as a primary bariatric and metabolic procedure for patients requiring weight loss and/or improvement in obesity-related complications
      • Note: OMA notes that increased risk of malabsorption with this procedure compared to sleep
    • All societies recommend RYGB for benefits for improvement in T2DM and related diabetic complications
      • ASMBS include note that Benefits of RYGB on T2D and hypertension are greater in adolescents than adults
  • Laparoscopic Adjustable Gastric Banding (LAGB):
    • Recommended by AACE to be considered as a primary bariatric and metabolic procedure for patients requiring weight loss and/or improvement in obesity-related complications
      • Note: OMA notes that optimally suited for lower BMI patients and those with no metabolic disease
    • ASMBS recommend for benefits related to joint health and ability to potentially avoid joint arthroplasties after weight loss from the LAGB procedure
  • Biliopancreatic Diversion with Duodenal Switch (BPD/DS):
    • Recommended by AACE to be considered as a primary bariatric and metabolic procedure for patients requiring weight loss and/or improvement in obesity-related complications
      • Note: OMA notes optimally suited for patients with higher BMI and T2DM, and while it may result in greatest weight loss benefit, it is associated with the highest rates of post-op vitamin & mineral deficiencies
      • ASMBS 2022 guidelines did not discuss this procedure
  • Loop Duodenal Switch:
    • Recommended by AACE to be considered as a primary bariatric and metabolic procedure for patients requiring weight loss and/or improvement in obesity-related complications
      • Note: OMA notes optimally suited for patients with higher BMI and T2DM, but long-term data for post-op monitoring/complications for this procedure was not available
      • ASMBS 2022 guidelines did not discuss this procedure
      • Endoscopic Sleeve Gastroplasty (ESG) & Vertical Sleeve Gastrectomy (VSG)
      • VSG recommended by AACE to be considered as a primary bariatric and metabolic procedure for patients requiring weight loss and/or improvement in obesity-related complications
        • AACE recommended use of preoperative endoscopy to be considered in all patients being evaluated for sleeve gastrectomy (ESG or VSG)
        • Note: OMA notes VSG can worsen GERD & Barrett’s esophagus, with AACE recommendation for PPI post-op for patients with de novo gastroesophageal reflex

As we navigate the intricate guidelines for bariatric surgery from OMA, AACE, ASMBS and other collaborating medical societies, a thorough understanding of these diverse recommendations can greatly enhance the care provided to obesity weight management patients. Integrating these guidelines ensures a comprehensive approach to obesity management, tailored to each patient’s unique needs. Staying vigilant and adaptable in evaluating evolving recommendations helps refine surgical weight management strategies, fostering collaborative decision-making and paving the way for each patient’s journey toward improved health and well-being.

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