Obesity is a disease that affects the entire patient, both physically and psychologically, and requires a multidisciplinary treatment approach for long-term success. Despite an increased focus on identifying and developing more effective treatments for obesity, an increased awareness of its associated comorbid conditions, and increasing costs on the healthcare system, its prevalence continues to rise. It is predicted that obesity will affect almost 50% of American adults by the year 2030.1
For some patients, bariatric surgery is a good treatment option.
METABOLIC AND BARIATRIC SURGERY AS AN EFFECTIVE OBESITY TREATMENT OPTION
Numerous clinical studies have demonstrated beneficial effects of bariatric surgery on weight loss, mostly compared with lifestyle intervention.2
More recent data has demonstrated that in addition to weight loss, bariatric surgery is also associated with decreased incidence of cancer and decreased risk of cardiovascular mortality compared to nonsurgical control subjects.4
All of these studies demonstrate the combined impact of bariatric surgery on weight loss along with decreased cardiovascular mortality.
Metabolic and bariatric surgery continues to become increasingly recognized (a 60% increase in the number of procedures performed has been noted since 2011) as the most effective and sustained treatment available for patient with moderate to severe obesity with associated medical conditions. These procedures are typically performed using minimally invasive techniques that result in short hospital stays and minimal postoperative pain. The advances the bariatric surgical field has continued to make in terms of patient safety and outcomes will no doubt continue to fuel the growth of this field.
The American Association of Clinical Endocrinologists (AACE
) Task Force on Obesity in 2011 recommended that surgery is indicated in high-risk patients with obesity and that significant evidence exists to classify obesity as a disease. AACE
updated obesity treatment guidelines in 2019, initially created in 2013, which was cosponsored by the American College of Endocrinology, The Obesity Society (TOS), American Society for Metabolic & Bariatric Surgery (ASMBS
), Obesity Medicine Association (OMA), and American Society of Anesthesiologists and subsequently endorsed by the American Society for Nutrition (ASN), the Obesity Action Coalition (OAC), and the American Society for Parenteral and Enteral Nutrition (ASPEN). These clinical practice guidelines provide valuable information pertaining to the preoperative and postoperative nutrition and metabolic and nonsurgical care for metabolic and bariatric patients.
Despite the documented benefits of bariatric surgery, healthcare professionals (HCPs) may be hesitant to recommend these procedures to their patients due to wanting to “do no harm”; questioning the long-term effectiveness of surgery; limited knowledge about
surgery; not wanting to recommend surgery too early; and not knowing if insurance would cover surgery.6
This chapter will address some of these knowledge gaps and review primary procedures commonly performed in the United States, indications, contraindications, and psychological and other special considerations when electing to refer a patient for metabolic and bariatric surgery in the primary care setting. This chapter will also discuss risks, as well as the short- and long-term results, that can be expected for the overwhelming majority of patients. Commonly held misconceptions will also be addressed, specifically through case examples that demonstrate the decision-making during the evaluation of the patient with obesity considering metabolic and bariatric surgery.
INDICATIONS AND CONTRAINDICATIONS
Indications for metabolic and bariatric surgery endorsed by the National Institutes of Health (NIH) are outlined in the publication “Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults.” The NIH specified that surgery is an effective obesity treatment option for patients with a BMI
of 40 kg/m2
or 35 kg/m2
with obesity-related comorbidities, primarily hypertension, T2D
, dyslipidemia, and obstructive sleep apnea (http://www.nhlbi.nih.gov/guidelines/obesity/ob_gdlns.pdf). Additionally, metabolic and bariatric surgery has been shown to be of value in patients with class 1 obesity (BMI
between 30 and 35 kg/m2
) and severe uncontrolled diabetes. While only a few insurance companies in the United States authorize surgery for patients in this category, it is fully supported within the European guidelines for metabolic and bariatric surgery.13
The center in which you refer your patient will know if class 1 obesity is a covered insurance benefit for your patient.
Absolute contraindications for metabolic and bariatric surgery may include, but are not limited to:
Uncontrolled bipolar disorder
Active substance abuse (drugs/alcohol)
Borderline personality disorder
Significant eating disorder
Defined noncompliance with previous medical or psychological care
Unwilling to comply with necessary guidelines following bariatric surgery
Hormonal causes of obesity that can be medically treated
Severe cardiopulmonary disease
Some surgeons may not consider schizophrenia as an absolute contraindication, but a relative contraindication depending on whether the patient is highly functional and has readily available psychiatric and psychological support in the postoperative period. Additionally, advanced cardiopulmonary disease may be considered a relative contraindication by some surgeons. It is imperative that you refer patients with increased risk to centers that are experienced in dealing with these types of complex issues.
Relative contraindications for metabolic and bariatric surgery in which a decision to proceed with surgery will be made on an individual basis include, but is not limited to:
History of cancer within previous 5 years
Collagen vascular disease
Inflammatory bowel disease (IBD)
Down syndrome or intellectual disability
Decisions to operate on patients are typically based on available resources at the metabolic and bariatric center and the discretion of the surgeon. Many surgeons will consider performing metabolic and bariatric surgery on patients with cancer prior to 5 years from their diagnosis if the cancer is associated with a low recurrence risk and are no longer receiving treatment. Advanced cirrhosis with portal hypertension would be considered an absolute contraindication by most surgeons. Furthermore, severe active ulcerative colitis or Crohn’s disease may be considered an absolute contraindication by most surgeons as it is preferable to perform surgery under conditions in which symptoms are stabilized (a case study below reviews a patient with IBD).
It is essential that patients receive preoperative education, medical and psychological evaluations, and dietary preparation (Table 9.1
). The preoperative evaluation must be comprehensive to identify potential treatable causes of obesity and determine factors that will increase risks for potential complications. The goal is to optimize, or prehabilitate, a patient’s health and modify risk factors to ensure surgery is performed under optimal conditions. A complete history and physical examination is performed to identify obesity-related comorbidities and indications for surgery. Routine laboratory tests may include a comprehensive metabolic profile (CMP) and complete blood count (CBC), lipid profile, thyroid function, urinalysis, prothrombin time/international normalized ratio (PT/INR), blood type, and micronutrient screening that includes iron studies, ferritin, vitamin B12, folic acid, and 25-OH vitamin D. Insurance companies may not cover all of these lab tests without the appropriate supporting diagnoses and, at a minimum, a CBC and CMP should be obtained. The nutrient screening is essential in the postoperative period and is usually covered by insurance with the supporting diagnosis of postsurgical malabsorption.
Dietary and psychological evaluations are vital in the preoperative assessment to identify possible areas of concern, such as binge eating disorder, night eating syndrome, or undiagnosed depression, which could compromise outcomes after surgery. To accomplish these goals, most insurance companies require that patients undergo a dietary and psychological assessment prior to bariatric surgery and are typically performed within the comprehensive bariatric surgical center. Furthermore, most centers have preoperative protocols that mandate attendance at one more group classes. Patients are taught how they will need to eat following surgery and learn coping strategies when faced with behavioral and dietary challenges. Understanding your patient’s
goals is important to the overall success after surgery as there may be discrepancies between a patient’s weight loss goals and the realistic weight loss potentially realized after surgery. Numerous factors may influence a patient’s ability to achieve an optimal result after surgery, including psychological profiles as described above, comorbidities, medications that may lead to suboptimal weight loss, age and metabolism, body composition, and energy balance. A comprehensive metabolic and bariatric surgery center is committed to identifying variations in any of these factors which may predispose a patient to insufficient weight loss outcomes or weight regain after experiencing a satisfactory weight nadir.
TABLE 9.1 Preoperative Checklist
PREOPERATIVE CHECKLIST FOR METABOLIC AND BARIATRIC SURGERY
Identify treatable causes of obesity and treat, if present
Look for inclusion criteria meeting the National Institutes of Health and insurance criteria
Note contraindications for surgery, if present
Document medical necessity for surgery including obesity-related comorbidities, weight, body mass index
Assess patient level of commitment
Identify history of cancer, if present
Assess for nicotine use (smoking, vaping, patch, chewing, etc.) and require nicotine cessation; refer for counseling if needed
Complete blood count and comprehensive metabolic profile, including fasting blood glucose and liver function tests, are routine during initial consultation
Other recommended labs, if indicated, include thyroid function, lipid profile and glycated hemoglobin, urinalysis, prothrombin time, and partial thromboplastin time
Type and screen just prior to surgery
Iron, TIBC, ferritin, vitamin B12, folic acid, 25-OH vitamin D, parathyroid hormone levels
Educate about dietary behavior required postsurgery
Educate about potential for vitamin and mineral deficiencies in the postoperative period
Review body composition and energy balance
Set weight loss goals and manage discrepancies
Assess healthy eating index and identify binge eating and night eating disorder, and treat if present
Assess overall mood and identify untreated depression, and treat if present
Assess for substance and alcohol abuse, and treat if present
Identify medications that may contribute to suboptimal weight loss
Assess overall support structure
Identify need for further behavioral support and counseling
Confirm patient has benefits covering metabolic and bariatric surgery
Preoperative weight management documentation
Documented weight loss prior to surgery
Cardiopulmonary evaluation is often required in patients interested in having metabolic and bariatric surgery. Cardiology evaluations for risk assessment should follow standards of practice for perioperative evaluation and management of patients undergoing noncardiac surgery, which may include electrocardiogram, echocardiogram, stress testing, and cardiac catheterization as indicated.14
Patients with previous history of unprovoked deep vein thrombosis or pulmonary embolism should undergo a formal hematology evaluation to rule out a hypercoagulable state. Pulmonary clearance should be obtained in patients with significant chronic obstructive pulmonary
disease in order to optimize patients prior to surgery. Chest x-rays are not routinely obtained unless clinically indicated. A sleep study is indicated in patients with significant snoring, witnessed apnea episodes, morning headaches, daytime sleepiness, and significant oxygen desaturation on overnight pulse oximetry. Screening using the Epworth Sleepiness Scale or STOP-BANG questionnaire may help to identify at-risk patients to refer for an overnight polysomnogram (Table 9.2
Patients newly diagnosed with obstructive sleep apnea should implement continuous positive airway pressure (CPAP
) treatment to optimize their pulmonary status for at least 1 month prior to surgery.
TABLE 9.2 Epworth Sleepiness Scale and STOP-BANG Questionnaire Used for Obstructive Sleep Apnea Screening
Epworth Sleepiness Scale
0-10: Normal range
Use the following point tabulation for each question
0: No chance of dozing
1: Minimal chance of dozing
2: Moderate chance of dozing
3: High chance of dozing
How likely are you to doze off or sleep during the following?
1. Sitting or reading?
2. Watching television?
3. Sitting inactive in a public space?
4. As a passenger in a car for an hour without a break?
5. Lying down to rest when circumstances permit?
6. Sitting and talking to someone?
7. Sitting quietly after lunch without alcohol?
8. In a car, while stopped for a few minutes in traffic?
0-2: Low risk
3-4: Intermediate risk
5-8: High risk
Use the following point tabulation for each question
S: Snore loudly?
T: Feel tired during the day?
O: Observe apnea while sleeping?
P: Treated for high blood pressure?
B: Body mass index ≥35 kg/m2
A: Age ≥50 years
N: Neck circumference
Male ≥17 inches
Female ≥16 inches
Gastrointestinal (GI) evaluations are often obtained as clinically indicated. Some centers routinely obtain esophagogastroduodenoscopy (EGD) on all patients, while others are more selective and perform preoperative EGDs only when indicated, such as a history of dyspepsia, reflux, dysphagia, or previous ulcer disease. Helicobacter pylori screening is not routinely performed but should be considered in regions of high prevalence and treated with triple antibiotic regimen if tested positive. A gallbladder ultrasound may be obtained routinely by some surgeons but is usually ordered selectively as clinically indicated. If cholelithiasis is present, surgeons may elect to perform a cholecystectomy concurrently with the metabolic and bariatric procedure.
Endocrine evaluations for patients with severe uncontrolled diabetes despite taking multiple medications should be considered since hyperglycemia is associated with increased risk for infection, poor wound healing, and extended hospitalization. A preoperative glycated hemoglobin level of ≤8% should be achieved, if possible. A serum thyroid-stimulating hormone level should be obtained if clinical evidence of hypothyroid is present and treated accordingly. Screening for PCOS
and Cushing syndrome should be only be conducted if clinically indicated.
The principal goal for the preoperative psychosocial evaluation in patients preparing for metabolic and bariatric surgery is to ensure patients are committed to the necessary lifelong changes after surgery, but most importantly to identify those with increased risk for potential relapse of preexisting depression or behavioral eating disorders and subsequently address potential issues that may contribute to a poor postoperative outcome.
Patients with class 2 (BMI
35.0 to 39.9 kg/m2
) and 3 (BMI
) obesity often carry a diagnosis of depression, anxiety, and other stress-related conditions including eating disorders. They also often battle with body image and poor self-esteem issues. The psychologist can help patients develop coping strategies to ensure a more positive outcome after surgery. To underscore the importance of having continued behavioral health services available in the postoperative period, patients with a diagnosed psychological health disorder were noted in one study to have 34% increased odds of 30-day readmission when compared with patients who did not have a mental health disorder diagnosis. The odds were even greater (46%) in patients diagnosed with depression or bipolar disorder. Careful consideration must be given to patients with depression taking antidepressants who undergo an RYGB
procedure as medication malabsorption may exacerbate symptoms.
An awareness of the potential for excessive alcohol and illicit substance use following surgery is critical as patients may seek substitutes to attain the dopaminergic reward previously achieved with food. Obesity-induced dysregulation of dopamine reward processing, in theory, can result in compensatory overeating, and this process is thought to be reversed after RYGB
Finally, there are some studies suggesting that there are potentially increased risks for self-harm and suicide after metabolic and bariatric surgery. However, other studies argue the increased risks were already present prior to surgery and that patients need to be monitored carefully in the postoperative period.17
A number of psychosocial issues that might potentially attribute to suicide include the lack of improvement in quality of life, physical limitation, sexual dysfunction, relationship, or low self-esteem. Additional factors to consider include a prior history of being abused or perceived postoperative failure due to insufficient weight loss or weight regain.
WEIGHT LOSS REQUIREMENTS PRIOR TO SURGERY
Preoperative medical weight management requirements with mandatory weight loss in the preoperative period is often imposed by many insurance companies, and patients may be denied surgery benefits if weight loss is not observed during this time period. However, there is no evidence to support that insurance-mandated preoperative weight loss results in decreased complication rates or improved outcomes after surgery and these practices should be abandoned as it causes unnecessary delays in receiving treatment, contributes to patient attrition, and leads to the progression of obesity-related comorbidities.18
A preoperative very low calorie diet (VLCD
) treatment is prescribed by many surgeons for up to 2 to 4 weeks prior to surgery to achieve substantial liver size reduction, which allows for better exposure of the gastroesophageal region during surgery. A 5% to 20% reduction in liver volume has been demonstrated in patients completing a preoperative VLCD
. Additionally, one study demonstrated that greater than 3.5% total weight loss in patients completing VLCD
4 weeks preoperatively was associated with significantly greater weight loss at 12 months postoperatively compared with patients who lost less weight.19
In 2018, approximately 252,000 metabolic and bariatric procedures were performed in the United States, noting a 60% increase in the number of procedures performed compared with 2011. VSG
is currently the most common procedure, representing 61% of procedures performed in the United States. The number of RYGB
procedures performed annually has been steadily declining since 2011 and currently account for 17% and 1.1% of all procedures, respectively. But there was slight increase in RYGB
noted in 2017 and 2018 in which RYGB
represented approximately 17% of all procedures. Revisions of previous metabolic and bariatric procedures, which will be briefly reviewed later in this chapter, continue to rise as increasing numbers of AGB
are removed and may soon surpass the number of RYGB
procedures being performed annually (Figure 9.5
Metabolic and bariatric surgery procedure trends: 2011-2018. RYGB
, Roux-en-Y gastric bypass; BPD
/DS, biliopancreatic diversions with duodenal switch.
SAFETY AND EFFICACY OF METABOLIC AND BARIATRIC SURGERY
Metabolic and bariatric surgical procedures are now among the safest performed in the United States. This extraordinary achievement is principally due to the introduction of laparoscopic techniques and national accreditation with a long-standing emphasis on patient safety and continuous quality improvement efforts.
Leading the way in quality improvement efforts is the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP
), a joint effort between the American College of Surgeons (ACS
) and the American Society of Metabolic and Bariatric Surgery (ASMBS
) developed standards that are designed to optimize patient safety and requires centers to enter patient demographic and outcomes data into a national data registry. This data registry allows a comprehensive analysis of safety and outcomes data on a large scale in which centers can use as an opportunity to improve structural and process deficiencies. (See Clinical Highlights for information on how you can refer your patient to an accredited center.)
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