- ACRONYMS AND DEFINITIONS
- AGA - American Gastroenterological Association
- ASMBS - The American Society for Metabolic and Bariatric Surgery
- BMD - Bone mineral density
- BPD/DS - Biliopancreatic diversion with duodenal switch
- DVT - Deep vein thrombosis
- ESG - Endoscopic sleeve gastroplasty
- GERD - Gastroesophageal reflux disease
- NAFLD - Nonalcoholic fatty liver disease
- NASH - Nonalcoholic steatohepatitis
- PCOS - Polycystic ovary syndrome
- RYGB - Roux-en-Y gastric bypass (Gastric bypass)
- SADI-S - Single anastomosis duodeno–ileal bypass with sleeve gastrectomy
- SR - Silastic ring
- VTE - Venous thromboembolism
- PROCEDURE RATES
- Overview
- Weight loss procedures have become increasingly common. In 2020, around 300,000 bariatric surgeries were performed in the U.S., which is equal to the number of cholecystectomies performed annually.
- The two most common procedures are gastric sleeve and gastric bypass (also called Roux-en-Y gastric bypass). Gastric bypass used to be the most common procedure, but around 2013, gastric sleeve surpassed it. Today, more than 60% of bariatric surgeries are gastric sleeve procedures, while gastric bypass makes up less than 20%. Reasons that gastric sleeve has become preferred include lower surgical complication rates, lower reoperation rates, and fewer chronic nutritional deficiencies.
- In 2019, an estimated 256,000 weight loss procedures were performed in the U.S.. The table below gives a breakdown of which procedures were performed.
Type of weight loss procedure performed in U.S. in 2019 (N=256,000 procedures) |
|
---|---|
Gastric sleeve | 59.4% |
Gastric bypass | 17.8% |
Revisional surgery✝ | 16.7% |
Gastric balloon | 1.8% |
Gastric banding | 0.9% |
BPD/DS | 0.9% |
Other | 2.4% |
- WEIGHT LOSS EFFECTS
Typical weight loss seen with obesity treatments | |
---|---|
Treatment | % weight loss from baseline (length of follow-up) |
BPD/DS | 35 - 40% (> 10 years) |
Gastric bypass | 30 - 35% (> 10 years) |
Gastric sleeve | 25 - 30% (> 10 years) |
Gastric banding | 20 - 25% (> 10 years) |
Wegovy (semaglutide) | 16% (68 weeks) |
Endoscopic sleeve gastroplasty | 11.4% (104 weeks) |
Intragastric balloon | 10% (6 months) |
Appetite suppressants (e.g. phentermine) | 10% (6 months) |
Qsymia (topiramate + phentermine) | 10% (56 weeks) |
Saxenda (Liraglutide) | 8% (56 weeks) |
Xenical (orlistat) | 7.6% (2 years) |
Contrave (naltrexone + bupropion) | 6.5% (28 weeks) |
Plenity (hydrogel) | 6.4% (24 weeks) |
- INDICATIONS
- ASMBS indications for bariatric procedures
- BMI ≥ 40 - any patient without coexisting medical problems who are not at excessive risk for surgical complications
- BMI ≥ 35 - patients with ≥ 1 severe obesity-related complication that is treatable with weight loss. Obesity-related complications include the following: type 2 diabetes, high risk for type 2 diabetes (insulin resistance, prediabetes, and/or metabolic syndrome), poorly controlled hypertension, NAFLD or NASH, obstructive sleep apnea, osteoarthritis of the knee or hip, and urinary stress incontinence. Other conditions that may also be considered but have weaker evidence for a benefit include the following: obesity-hypoventilation syndrome and Pickwickian syndrome after a careful evaluation of operative risk, idiopathic intracranial hypertension, GERD, severe venous stasis disease, impaired mobility due to obesity, and considerably impaired quality of life.
- BMI 30 - 34.9 - patients with type 2 diabetes and inadequate glycemic control despite optimal lifestyle and medical therapy should be considered for a bariatric procedure
- The BMI criterion for bariatric procedures should be adjusted for ethnicity (e.g. for Asians: 18.5 – 22.9 is healthy range; 23 – 24.9 overweight; and ≥ 25 obese) [1]
- PREPROCEDURAL EVALUATION
- The ASMBS recommends the following workup in patients who are being considered for bariatric procedures
- Complete history and physical including psychological evaluation
- Nutritional evaluation by a registered dietician
- Lab work
- All patients
- CBC, CMP, Lipid profile, TSH, Urinalysis, PT/INR, Blood type
- Iron studies
- Vitamin B12
- Folic acid (RBC folate, homocysteine, methylmalonic acid are optional)
- Vitamin D
- Certain patients
- Hemoglobin A1C if diabetic or prediabetic
- Vitamin A and E - consider in patients undergoing BPD/DS or RYGB
- Whole-blood thiamine (B1) levels may be considered in patients before bypass procedures (RYGB and BPD/DS)
- PCOS workup if clinically indicated (free and total testosterone, DHEA-S, and 17-hydroxyprogesterone (17-OHP))
- Cushing's syndrome screening if clinically indicated (e.g. 1-mg overnight dexamethasone test, 24-hour urinary free cortisol, 11 PM salivary cortisol)
- H. pylori testing in areas of high prevalence
- ECG (also consider ECHO in appropriate patients)
- Sleep study
- Liver evaluation and/or upper endoscopy, if clinically indicated (e.g. elevated LFTs, symptoms of cholelithiasis)
- Complete all recommended cancer screening
- Estrogen therapy should be discontinued before a bariatric procedure (1 cycle of oral contraceptives in premenopausal women; 3 weeks of hormone replacement therapy in postmenopausal women) to reduce the risks for postprocedure VTE
- Patients who smoke cigarettes should stop as soon as possible, preferably 1 year, but at the very least, 6 weeks before bariatric procedures
- Patients with a history of DVT or cor pulmonale should be evaluated for ongoing DVT [1]
- POSTOPERATIVE CARE
Vitamin and mineral recommendations |
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Vitamin B1 (thiamine)
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Vitamin B12 (cobalamin)
|
Folic acid (folate)
|
Iron
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Vitamin D and calcium
|
Vitamin A
|
Vitamin E
|
Vitamin K
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Zinc
|
Copper
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Selenium
|
- GASTRIC SLEEVE
- Procedure
- Gastric sleeve, also called sleeve gastrectomy, is a procedure where the surgeon removes 80% of the stomach and sutures it back together, leaving a "sleeve" of stomach that is shaped like a banana.

- Advantages
- Surgery is simpler than gastric bypass and takes less time
- Can be performed in certain patients with high-risk medical conditions
- May be performed as the first step for patients with severe obesity
- May be used as a bridge to gastric bypass or SADI-S procedures
- Effective weight loss and improvement of obesity-related conditions
- Disadvantages
- Non-reversible procedure
- May worsen or cause new-onset reflux and heartburn
- Less impact on metabolism compared to bypass procedures [11]
- The SM-BOSS trial enrolled 217 morbidly obese adults in Switzerland
Main inclusion criteria
- Age 18 - 65 years
- BMI > 40 or > 35 with ≥ 1 comorbidity
- Failed conservative treatments for 2 years
Main exclusion criteria
- Severe GERD despite meds
- Large hiatal hernia
- Previous bariatric surgery
- Inflammatory bowel disease
Baseline characteristics
- Average age 43 years
- Female sex - 72%
- Average weight - 273 lbs (124 kg)
- Average BMI - 44
- Type 2 DM - 25%
Randomized treatment groups
- Group 1 (107 patients): Laparoscopic sleeve gastrectomy
- Group 2 (110 patients): Laparoscopic Roux-en-Y gastric bypass (RYGB)
- Treatment was unblinded
Primary outcome: Weight loss, defined as percentage excess BMI loss (100 × [baseline BMI − follow-up BMI]/[baseline BMI − 25]), over a 5-year period
Results
Duration: 5 years | |||
Outcome | Gastric sleeve | RYGB | Comparisons |
---|---|---|---|
Weight loss | 73 lbs (33 kg) | 81 lbs (36.6 kg) | p=0.19 |
Percent weight loss | 25% | 28.6% | p=0.02 |
Primary outcome (excess BMI loss) | 61% | 68% | p=0.22 |
Post-op intervention | 15.8% | 22.1% | N/A |
Overall mortality | 0% | 1.9% | N/A |
|
Findings: Among patients with morbid obesity, there was no significant
difference in excess BMI loss between laparoscopic sleeve gastrectomy and laparoscopic
Roux-en-Y gastric bypass at 5 years of follow-up after surgery.
- The study enrolled 114 obese adults with types 2 diabetes in New Zealand
Main inclusion criteria
- Age 20 - 55 years
- Type 2 diabetes for ≥ 6 months
- BMI 35 - 65 for ≥ 5 years
Main exclusion criteria
- C-peptide < 350 pmol/L
- Type 1 diabetes
- Current smoker
- Chronic pancreatitis
Baseline characteristics
- Average age 46 years
- Female sex - 52%
- Average weight - 275 lbs (125 kg)
- Average BMI - 42.8
- Average A1C - 7.9%
Randomized treatment groups
- Group 1 (56 patients): Silastic ring laparoscopic Roux-en-Y gastric bypass (SR-LRYGB)
- Group 2 (58 patients): Laparoscopic sleeve gastrectomy (LSG)
- Treatment was double-blinded
- SR-LRYGB is gastric bypass with a silastic ring placed around the pouch just above its connection with the jejunum. The ring prevents the pouch from expanding and can increase the long-term success of the procedure.
Primary outcome: A hemoglobin A1C level of < 6% (42 mmol/mol) without any glucose-lowering medications at 5 years (American Diabetes Association criteria for complete remission of type 2 diabetes)
Results
Duration: 5 years | |||
Outcome | SR-LRYGB | LSG | Comparisons |
---|---|---|---|
Primary outcome | 48% | 31% | p=0.015 |
% weight loss | 26.9% | 16.3% | p<0.001 |
Body weight lost | 73 lbs (33.3 kg) | 46.4 lbs (21.1 kg) | p<0.05 |
|
Findings: SR-LRYGB provided superior diabetes remission and weight loss compared with
LSG at 5 years, with similar low risks of complications
- Summary
- In the two studies above, gastric bypass led to greater weight loss than gastric sleeve at 5 years. The difference was more pronounced in the SR-LRYGB study (26.9% vs 16.3%) than in the SM-BOSS study (28.6% vs 25%). The SR-LRYGB study was unique in that participants and researchers were blinded to the procedure that was performed. In both studies, gastric bypass had a slightly higher complication rate. Gastric sleeve was more effective in the SM-BOSS study (25% vs 16.3% weight loss), which took place at 4 bariatric centers in Switzerland; the SR-LRYGB study was a single-center study in New Zealand. Given these differences in demographics and design, it's difficult to make comparisons between the studies.
- GASTRIC BYPASS
- Procedure
- Gastric bypass, also called Roux-en-Y gastric bypass (RYGB), is a procedure where the upper part of the stomach is made into a pouch about the size of an egg. The small intestine is then cut between the duodenum and jejunum, and the jejunum is brought up and connected to the pouch. The remaining stomach and duodenum are connected to the jejunum several feet down from the pouch. Some surgeons perform a variation of the surgery, where a silastic ring is placed around the pouch just above its connection with the jejunum. The ring prevents the pouch from expanding and can increase the long-term success of the procedure (gastric bypass with silastic ring)

- Advantages
- Causes reliable and long-lasting weight loss
- Has been performed for more than 50 years
- The procedure treats gastric reflux
- Disadvantages
- More complex surgery than gastric sleeve
- Higher reoperation rate and more chronic vitamin and mineral deficiencies than gastric sleeve
- May cause small bowel complications
- Increased risk of developing ulcers, especially with NSAID or tobacco use
- May cause "dumping syndrome," a condition where food, especially sugars, move into the small bowel too quickly and cause abdominal cramping and diarrhea
- If silastic ring is used, erosion of the ring into the stomach can occur [11]
- The SM-BOSS trial enrolled 217 morbidly obese adults in Switzerland
Main inclusion criteria
- Age 18 - 65 years
- BMI > 40 or > 35 with ≥ 1 comorbidity
- Failed conservative treatments for 2 years
Main exclusion criteria
- Severe GERD despite meds
- Large hiatal hernia
- Previous bariatric surgery
- Inflammatory bowel disease
Baseline characteristics
- Average age 43 years
- Female sex - 72%
- Average weight - 273 lbs (124 kg)
- Average BMI - 44
- Type 2 DM - 25%
Randomized treatment groups
- Group 1 (107 patients): Laparoscopic sleeve gastrectomy
- Group 2 (110 patients): Laparoscopic Roux-en-Y gastric bypass (RYGB)
- Treatment was unblinded
Primary outcome: Weight loss, defined as percentage excess BMI loss (100 × [baseline BMI − follow-up BMI]/[baseline BMI − 25]), over a 5-year period
Results
Duration: 5 years | |||
Outcome | Gastric sleeve | RYGB | Comparisons |
---|---|---|---|
Weight loss | 73 lbs (33 kg) | 81 lbs (36.6 kg) | p=0.19 |
Percent weight loss | 25% | 28.6% | p=0.02 |
Primary outcome (excess BMI loss) | 61% | 68% | p=0.22 |
Post-op intervention | 15.8% | 22.1% | N/A |
Overall mortality | 0% | 1.9% | N/A |
|
Findings: Among patients with morbid obesity, there was no significant
difference in excess BMI loss between laparoscopic sleeve gastrectomy and laparoscopic
Roux-en-Y gastric bypass at 5 years of follow-up after surgery.
- The study enrolled 114 obese adults with types 2 diabetes in New Zealand
Main inclusion criteria
- Age 20 - 55 years
- Type 2 diabetes for ≥ 6 months
- BMI 35 - 65 for ≥ 5 years
Main exclusion criteria
- C-peptide < 350 pmol/L
- Type 1 diabetes
- Current smoker
- Chronic pancreatitis
Baseline characteristics
- Average age 46 years
- Female sex - 52%
- Average weight - 275 lbs (125 kg)
- Average BMI - 42.8
- Average A1C - 7.9%
Randomized treatment groups
- Group 1 (56 patients): Silastic ring laparoscopic Roux-en-Y gastric bypass (SR-LRYGB)
- Group 2 (58 patients): Laparoscopic sleeve gastrectomy (LSG)
- Treatment was double-blinded
- SR-LRYGB is gastric bypass with a silastic ring placed around the pouch just above its connection with the jejunum. The ring prevents the pouch from expanding and can increase the long-term success of the procedure.
Primary outcome: A hemoglobin A1C level of < 6% (42 mmol/mol) without any glucose-lowering medications at 5 years (American Diabetes Association criteria for complete remission of type 2 diabetes)
Results
Duration: 5 years | |||
Outcome | SR-LRYGB | LSG | Comparisons |
---|---|---|---|
Primary outcome | 48% | 31% | p=0.015 |
% weight loss | 26.9% | 16.3% | p<0.001 |
Body weight lost | 73 lbs (33.3 kg) | 46.4 lbs (21.1 kg) | p<0.05 |
|
Findings: SR-LRYGB provided superior diabetes remission and weight loss compared with
LSG at 5 years, with similar low risks of complications
- Summary
- In the two studies above, gastric bypass led to greater weight loss than gastric sleeve at 5 years. The difference was more pronounced in the SR-LRYGB study (26.9% vs 16.3%) than in the SM-BOSS study (28.6% vs 25%). The SR-LRYGB study was unique in that participants and researchers were blinded to the procedure that was performed. In both studies, gastric bypass had a slightly higher complication rate. Gastric sleeve was more effective in the SM-BOSS study (25% vs 16.3% weight loss), which took place at 4 bariatric centers in Switzerland; the SR-LRYGB study was a single-center study in New Zealand. Given these differences in demographics and design, it's difficult to make direct comparisons between the studies.
- GASTRIC BANDING
- Procedure
- The gastric band is a silicone device that is placed around the top part of the stomach. The band restricts the size of the upper stomach so that the amount a person can eat is limited. The circumference of the band can be adjusted by injecting fluid through a subcutaneous port connected to the band.

- Advantages
- Less invasive than gastric sleeve and bypass
- Patient can go home the same day
- The band can be removed if needed
- Lower risk of long-term nutritional deficiencies
- Disadvantages
- The band often requires adjusting, particularly during the first year
- Less weight loss than other procedures
- The band may move or slip
- The band can erode through the stomach
- High reoperation rate
- May cause swallowing problems and enlargement of the esophagus [11]
- ENDOSCOPIC SLEEVE GASTROPLASTY
- Procedure
- Endoscopic sleeve gastroplasty (ESG) is a bariatric procedure where an endoscope is advanced into the stomach, and a special device is used to suture part of the stomach lumen together, reducing its size. The intent is to achieve an effect similar to sleeve gastrectomy without the surgery. The procedure is performed under general anesthesia in the outpatient setting, allowing most patients to go home the same day.
- Advantages
- No invasive surgery
- Lower cost than sleeve gastrectomy
- No hospital stay
- Disadvantages
- Newer procedure with less long-term data
- May require a "retightening" if response is lost or suboptimal
- The MERIT trial enrolled 209 adults with a BMI of 30 - 40
Main inclusion criteria
- Age 21 - 65 years
- BMI of 30 - 40
- Failed non-surgical weight loss methods
Main exclusion criteria
- Inflammatory bowel disease
- Gastric mass or polyps > 1 cm in size
- Hiatal hernia w/ > 4 cm axial displacement
- History of GI surgery
- Diabetes requiring insulin
Baseline characteristics
- Average age 46 years
- Female - 86%
- Average weight - 216 lbs (98 kg)
- Average BMI - 35
- Diabetes - 27%
Randomized treatment groups
- Group 1 (77 patients): Endoscopic sleeve gastroplasty + lifestyle modification
- Group 2 (110 patients): Lifestyle modification, including low-calorie diet plan and physical activity counseling
- After 52 weeks, patients in the ESG group could receive retightening either on the basis of a suboptimal response to the primary intervention or at the discretion of the treating investigator
- After 52 weeks, patients in the control group could crossover to ESG
- All patients were followed for 104 weeks
Primary outcome: Percentage of excess weight loss (EWL) at 52 weeks, where EWL = weight loss / (actual body weight - body weight if BMI was 25) X 100.
Results
Duration: 52 weeks | |||
Outcome | ESG | Lifestyle | Comparisons |
---|---|---|---|
Primary outcome (EWL) | 49.2% | 3.2% | p<0.0001 |
% weight loss (52 weeks) | 13.6% | 0.8% | p<0.0001 |
Body weight lost | 29.5 lbs (13.4 kg) | 1.8 lbs (0.8 kg) | N/A |
|
Findings: ESG is a safe intervention that resulted in significant weight loss, maintained at 104 weeks, with
important improvements in metabolic comorbidities. ESG should be considered as a synergistic weight loss
intervention for patients with class 1 or class 2 obesity.
- BILIOPANCREATIC DIVERSION WITH DUODENAL SWITCH (BPD/DS)
- Procedure
- A BPD/DS procedure starts with a sleeve gastrectomy. The duodenum is then separated from the stomach, and the ileum is cut approximately 250 cm from the cecum. The ileum is then brought up and connected to the stomach. The duodenum and the remaining small intestine are connected to the ileum about 100 cm from the cecum.
- Advantages
- Causes the most weight loss of all the procedures
- Affects intestinal hormones and reduces hunger
- Very effective at treating type 2 diabetes
- Disadvantages
- More complex procedure with higher complication rate
- Carries greatest risk of long-term vitamin and mineral deficiencies
- May worsen or cause new-onset reflux and heartburn
- Bowel movements may become looser and more frequent [11]
- INTRAGASTRIC BALLOON
- Procedure
- The intragastric balloon is a device placed in the stomach through endoscopy. The device is then filled with normal saline causing it to expand to the size of a grapefruit and occupy space in the stomach. Theoretically, this slows digestion and causes a sensation of fullness and satiety that leads to weight loss. The balloon is left in place for 6 months, at which time it is deflated and removed endoscopically. In the U.S., only the Orbera® balloon system is currently available. Another balloon system called ReShape® was approved in 2015, but in 2018, the manufacturer of Orbera® bought ReShape® and discontinued it. See the Orbera website for more.

- Advantages
- Balloon is placed endoscopically during an outpatient procedure that lasts about 20 minutes
- Balloon can easily be removed
- Disadvantages
- Less weight loss than other procedures
- Balloon must be removed after 6 months, and weight is often gained back
- Must take acid-suppressing medications to prevent stomach ulcers
- High rate of nausea and vomiting which may require early removal
- The trial enrolled 255 obese adults with a BMI of 30 - 40
Main inclusion criteria
- BMI 30 - 40
- Obesity for at least 2 years
- Failed conservative weight loss (e.g. diet, exercise)
Main exclusion criteria
- History of GI surgery (except appy or choly)
- History of GI obstruction
- GI motility disorder
- Significant hiatal hernia
- Positive H pylori at screening
- Inflammatory bowel disease
Baseline characteristics
- Average age 39 years
- Female sex - 90%
- Average weight - 215 pounds
- Average BMI - 35
Randomized treatment groups
- Group 1 (125 patients) - Orbera intragastric balloon for 6 months + Lifestyle intervention
- Group 2 (130 patients) - Lifestyle intervention
- The 12-month lifestyle intervention program incorporated the following elements: a low calorie (1000–1500 calories per day) diet, daily food and exercise diary, encouragement to exercise and emphasis on behavioral change during a total of 21 visits (9 visits in months 1–6, 12 visits in months 7–12)
Primary outcome: Difference in the average percent excess weight loss (%EWL) between groups at 9 months and difference in patients with ≥ 15% EWL at 9 months. Percent excess weight loss = Weight loss/(actual body weight - body weight if BMI was 25) X 100.
Results
Duration: 12 months | |||
Outcome | Orbera + Lifestyle | Lifestyle | Comparisons |
---|---|---|---|
Weight loss (6 months) | 21.8 lbs (9.9 kg) | 10.2% | 7 lbs (3.2 kg) | 3.3% | p<0.001 |
Weight loss (9 months) | 19.4 lbs (8.8 kg) | 9.1% | 7 lbs (3.2 kg) | 3.4% | p<0.001 |
Weight loss (12 months) | 16.3 lbs (7.4 kg) | 7.6% | 6.8 lbs (3.1 kg) | 2.9% | p<0.001 |
Primary outcome (%EWL at 9 months) | 26.5% | 9.7% | N/A |
Primary outcome (≥15% EWL at 9 months) | Orbera 45.6% more than control | p<0.001 | |
|
Findings: Intragastric balloon achieved greater short-term weight loss at 3 and 6 months postballoon removal than lifestyle intervention alone. Adverse gastrointestinal events were common.
- AGA 2021 recommendations
- The AGA suggests the use of the intragastric balloon (IGB) in individuals with obesity seeking a weight-loss intervention who have failed a trial of conventional weight-loss strategies
- Individuals who receive an IGB should also receive moderate- to high-intensity concomitant lifestyle modification interventions
- Patients with an IGB should receive prophylactic therapy with a proton pump inhibitor to prevent stomach ulcers and bleeding
- Patients who receive an IGB should receive an antiemetic regimen for 2 weeks after placement
- Perioperative laboratory screening for nutritional deficiencies is not recommended
- Daily supplementation with 1 - 2 adult multivitamins is recommended during placement [12]
- Summary
- In the trial above, the Orbera intragastric balloon improved weight loss by about 7% compared to control while it was in place. After removal, patients gained back weight, and at 6 months post-removal, the difference in weight loss was only 4.6%. The weight loss benefit would likely disappear with longer follow-up. Side effects were common, and 19% of patients who received the device had it removed before 6 months.
- In 2018, the FDA issued a safety alert stating that since 2016, a total of 12 patient deaths worldwide have been reported involving the Orbera Intragastric Balloon System and the ReShape Integrated Dual Balloon System
- GASTRIC ASPIRATION DEVICE
- Overview
- In 2016, the FDA approved the AspireAssist gastric aspiration device. AspireAssist is a gastrostomy tube that is implanted through the abdominal wall and into the stomach. The device has a port on the skin that connects to the gastrostomy tube. Twenty to thirty minutes after consuming a meal, the patient connects an external drainage device to the skin port and drains the gastric contents into the toilet. This typically removes 30% of consumed calories.
- In February 2022, the company that makes AspireAssist announced that they were discontinuing it effective April 8, 2022 (see Aspire Bariatrics for more).
- The PATHWAY trial enrolled 171 obese patients with a BMI of 35 - 55
Main inclusion criteria
- BMI 35 - 55
- 21 - 65 years old
- Failed at least 3 months of conservative weight loss measures
- No weight change > 3% within 3 months
Main exclusion criteria
- Previous upper GI surgery or pathology that would interfere with gastrostomy tube
- Refractory gastric ulcers
- Inflammatory bowel disease
- Diabetes treated with insulin or sulfonylurea
- HgA1C > 9.5%
- Significant pulmonary or cardiovascular disease
- Osteoporosis
- Taking medications that cause weight loss within 3 months
Baseline characteristics
- Average age 44 years
- Average BMI - 41
- Average weight - 251 lbs (114 kg)
- Female sex - 87%
Randomized treatment groups
- Group 1 (111 patients) - Implantation of AspireAssist device
- Group 2 (60 patients) - No implantation (control group)
- All patients received diet and exercise counseling once a month for 12 months
Primary outcome: 1. Percent excess weight loss (%EWL) at 52 weeks 2. Percent of patients who lost ≥ 25% of EWL at 52 weeks. Percent excess weight loss = Weight loss/(actual body weight - body weight if BMI was 25) X 100.
Results
Duration: 52 weeks | |||
Outcome | AspireAssist | Control | Comparisons |
---|---|---|---|
Percent excess weight loss | 32% | 10% | diff 21.7%, 95%CI [15% to 28%], p=0.0083 |
Percent losing ≥ 25% of EWL | 57% | 22% | diff 34%, p<0.05 |
Percent of total body weight lost | 12.1% | 3.6% | diff 8.6%, 95%CI [6.2% to 10.9%] |
Average weight loss | 30 lbs | 9 lbs | diff 21.6 lbs, 95%CI [16 to 27] |
Study discontinuations | 26% | 48% | N/A |
|
- Summary
- In the PATHWAY trial, the AspireAssist device caused significant weight loss compared to control. In practical terms, a patient weighing 251 pounds can expect an additional 22 lbs of weight loss over 52 weeks with the device. The device is invasive and requires daily hygiene and operational maintenance.
- The manufacturer discontinued the device in 2022
- VAGAL NERVE BLOCKADE
- Overview
- In 2015, the FDA approved an implantable device called the Maestro Rechargeable System to treat obesity. The device is implanted in the abdomen, where it sends intermittent electrical pulses to the vagus nerve at the gastroesophageal junction. The vagus nerve is involved in regulating stomach emptying and signaling to the brain that the stomach feels empty or full. The electrical impulses block nerve activity between the brain and stomach. The mechanism by which this causes weight loss is unknown. The device can be charged and adjusted through an external controller. The device was approved based on results from the ReCharge Study presented below.
- The company that makes the system, Enteromedics, changed its name to ReShape Lifesciences in 2017. The ReShape website does not mention the Maestro system, so it appears to no longer be available. The FDA website says that it is no longer marketed as of September 2018 (see FDA website).
- The ReCharge study enrolled 239 obese patients
Main inclusion criteria
- BMI 40 - 45, or BMI 35 - 39 with ≥ 1 obesity-related condition (hypertension, diabetes, dyslipidemia, sleep apnea, cardiomyopathy)
Main exclusion criteria
- History of bariatric surgery
- Hiatal hernia (> 5 cm)
- History of inflammatory bowel disease
- Medications for weight loss within 3 months
- Chronic treatment with narcotic analgesics
Baseline characteristics
- Average age 47 years
- Female sex - 84%
- Average BMI - 41
- Average weight - 251 lbs (114 kg)
Patients were randomized in a 2:1 ratio to one of two groups:
- Group 1 (162 patients) - Vagal nerve blockade device + weight management program
- Group 2 (77 patients) - Sham device + weight management program
- Patients in Group 2 had the device implanted, but it was not able to function
- In Group 1, the device delivered a charge for at least 12 hours a day. The charge was increased via a protocol to a desired charge, depending on patient tolerance. The device was recharged at least twice a week for 30 - 90 minute intervals.
Primary outcome: Coprimary efficacy objectives were to determine whether the vagal nerve block was superior in mean
percentage excess weight loss to sham by a 10-point margin with at least 55% of patients in the vagal block group achieving a 20% loss and 45% achieving a 25% loss. Percent excess weight loss = Weight loss/(actual body weight - body weight if BMI was 25) X 100
Results
Duration: 12 months | |||
Outcome | Vagal nerve blockade | Sham | Comparisons |
---|---|---|---|
Percent excess weight loss | 24.4% | 15.9% | diff 8.5%, 95%CI [3.1 - 13.9] |
Percent of actual body weight lost | 9.2% | 6% | diff 3.2%, 95%CI [1.1 - 5.2] |
Heartburn | 23% | 4% | N/A |
Pain, other | 23% | 0% | N/A |
Abdominal pain | 12% | 3% | N/A |
Dysphagia | 8% | 0% | N/A |
Burping | 8% | 0% | N/A |
Nausea | 7% | 1% | N/A |
Chest pain | 6% | 3% | N/A |
|
Findings: Among patients with morbid obesity, the use of vagal nerve block therapy compared with a sham control device did not meet either of the prespecified coprimary efficacy objectives, although weight loss in the vagal block group was statistically greater than in the sham device group. The treatment was well tolerated, having met the primary safety objective.
- Summary
- In the ReCharge study, the vagal nerve stimulator was slightly better than a sham procedure for weight loss, but it did not meet its prespecified goal. In practical terms, someone with a bodyweight of 251 pounds and a BMI of 41 can expect to lose an average of 8 additional pounds after one year with the stimulator. Patients with the device are also at greater risk for significant side effects.
- The system appears to no longer be available
- GLP DRUGS FOR WEIGHT REGAIN
- For patients who regain weight after surgery, options are limited. The highly-effective GLP weight-loss drugs (e.g. semaglutide, liraglutide) are an emerging option, but clinical data on their use in this patient population is sparse. The studies below evaluated GLP drugs in bariatric surgery patients who regained weight after their procedure; the first one is a randomized controlled trial, and the others are observational.
- Liraglutide vs Placebo in Patients with Persistent DM after Bariatric Surgery, Lancet Diabetes Endocrinol (2019)
- Retrospective Analysis of Semaglutide in Patients with Weight Regain after Bariatric Surgery, Obes Surg (2022)
- Retrospective Study of Semaglutide and Liraglutide in Patients with Weight Regain after Bariatric Surgery, Obes Surg (2023)
- Retrospective Analysis of Semaglutide and Liraglutide in Patients with Weight Regain after Bariatric Surgery, Obesity (2023)
- Retrospective Analysis of Liraglutide in Patients with Weight Regain after Bariatric Surgery, Eat Weight Disord (2022)
- BIBLIOGRAPHY
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