Continuing Education Activity

Bariatric surgery is an effective intervention for the treatment of patients with obesity. It is major surgery, and therefore appropriate counseling is essential to ensure patients can make informed decisions regarding their treatment. This activity reviews the current management and highlights the role of the interprofessional team in improving care for patients with obesity undergoing bariatric surgery.

Objectives:

• Describe the eligibility criteria for referral to bariatric surgery.
• Summarize the key patient counseling points for patients undergoing bariatric surgery.
• Identify the most common complications following bariatric surgery.
• Explain the importance of peri-operative support, including post-operative nutritional requirements.

Introduction

The number of people with obesity is increasing rapidly on a global scale, and obesity is one of the top causes of preventable death worldwide.[1] Obesity is associated with the development of cardiovascular disease (CVD), type 2 diabetes (T2DM), dyslipidemia (HLP), obstructive sleep apnoea (OSA), and some cancers amongst a host of other conditions.

Body mass index (BMI) has historically been used to categorize obesity. However, this should be used cautiously in patients with very high or very low muscle mass. BMI is calculated using the formula weight in kilograms, divided by height in meters squared. It is recommended that BMI is used alongside waist circumference and the presence of comorbidities (CVD, HTN) to risk-stratify patients. Weight management can be an area that is difficult to navigate without offending. However, it is important to highlight that use of the term “obese” refers to a clinical diagnosis that has specific health implications and is not an observation of the appearance of the individual.

It is important to recognize that the development of obesity is often multi-factorial, and a thorough history is indicated to explore any modifiable contributory factors such as lifestyle, medication, comorbidities, and psychological health. Meta-analyses have shown that dieting does not lead to sustained weight loss or improved health benefits.[2] However, bariatric surgery remains an effective clinical intervention for people with obesity compared with non-surgical treatments, including medical treatments such as orlistat.[3] Bariatric surgery is the most effective intervention for patients with a BMI > 40.[4]

Function

Those with a BMI of 30 - 34.9 with metabolic syndrome or uncontrolled diabetes mellitus; BMI 35 to 39.9 kg/m with one or more significant co-morbidity including CVD, HTN, OSA, HLP; and those with a BMI greater than or equal to 40 kg/m should be considered for bariatric surgery. To be eligible for surgery, all patients must undertake a weight reduction program. These programs should be multifactorial and include interventions targeted to reduce energy intake, improve the quality of diet, and increase activity levels. Programs such as these are also an opportunity to further assess factors contributing to obesity, such as psychological health and lifestyle behaviors. They are also used to identify whether patients have the level of commitment needed to comply with post-operative dietary recommendations.[5] Patients must be generally fit enough to undergo general anesthesia and surgery.

The care provided should be from the multi-disciplinary team, including but not limited to; surgeons, dieticians, family physicians, and psychologists. Patients should be counseled on the risks and benefits and the potential complications of the surgery to be able to make an informed decision. Patients should be aware that they will be followed up for a minimum of two years, including dietetics monitoring, medication reviews, physical and psychological support. Patients will be on lifelong vitamin supplementation and require interval monitoring of blood tests, including parathyroid hormone, vitamin D, calcium, full blood count, vitamin B12 and folate, iron studies, magnesium, and phosphate. They may be referred to the Plastics team for cosmetic surgery such as apronectomy post-bariatric surgery if appropriate. Referral to support groups can be a useful resource for patients and clinicians. If, after two years, patients can be discharged from bariatric surgical services, they ought to continue to have annual monitoring of their nutritional and mineral state.

Bariatric surgery is divided into two categories; restrictive and malabsorptive. Restrictive techniques are devised to produce early satiety by reducing the size of the stomach, and therefore a reduction in food intake. Commonly used restrictive procedures include laparoscopic sleeve gastrectomy (LSG) and laparoscopic adjustable gastric band. Malabsorptive procedures include biliopancreatic diversions with or without duodenal switch. They aim to induce a state of malabsorption similar to short bowel syndrome by reducing the length of the bowel. The Roux-en-Y gastric bypass (REYGB) is a combination of both methods. LSG and REYBG are the most commonly used methods.[6] A meta-analysis found that all types of bariatric surgery led to a substantial and maintained reduction in weight.[7]

The average length of stay in the hospital following REYGB is one day and two days following LSG. BMI > 50 and sleeve gastrectomy were both associated with a longer postoperative admission.[8] There is a role in enhancing recovery after surgery (ERAS) in reducing admission length in bariatric surgery for suitable patients.[9] The rate of early (<30 days) post-operative complications is higher with REYGB than LSG. However, this does not lead to an increase in 30-day mortality, re-admission rate, or reoperation rate.[10]

There is no difference in the rate of late complications between the two procedures.[11] After a gastric band, patients can expect to be able to return to work after one to two weeks and two to three weeks following a bypass, or LSG.

Issues of Concern

It is essential that clear post-operative dietary guidance is given and follow-up provided. Bariatric patients must take lifelong vitamin supplements following their procedure; however, studies suggest compliance declines at 5 months and is significantly reduced 2 to 3 years later.[12] Vitamin B12 and iron are the most commonly encountered deficiencies following surgery, and particular attention should be paid to the latter in menstruating women. Supplements can include Vitamins A, B12, C, D, calcium, magnesium, phosphate, iron, folic acid, zinc, copper, selenium, and thiamine. 

Surgical failure can be due to surgical complications requiring revision, insufficient weight loss, or weight regain following surgery. Revision surgery carries a higher risk than the initial surgery due to irreversible anatomical changes that have already been made in the primary surgery and the development of adhesions. Weight regain following surgery requires further studies to understand the mechanisms involved. Proposed contributing factors include inadequate follow-up and the development of detrimental lifestyles and behaviors. The desired reduction in the volume of food intake and, therefore, calorie intake with restrictive bariatric surgeries can be circumnavigated with items such as ice creams and milkshakes, which are particularly high in calories. Weight regain is particularly noted following sleeve gastrectomy, and this further emphasizes the importance of continued postoperative care.[13] 

Depressive disorders, binge eating, and uncontrolled snacking have been associated with poorer weight loss outcomes. To this end, most American bariatric programs require a pre-operative psychological assessment to identify any potentially detrimental factors.[14] Psychological intervention is most effective when offered post-operatively, and cognitive behavioral therapy (CBT) targeted towards eating behaviors is the most effective intervention.[12]

Clinical Significance

There are over 250,000 bariatric surgeries in the USA each year. There is substantial data suggesting surgery results in improved outcome measures when compared with medical treatment alone.[15] T2DM has previously been thought of as a chronic, incurable disease, with 50% of patients requiring insulin by 10 years. Bariatric surgery offers a way of sustained improvement or even leading to resolution of T2DM in patients with difficult to manage, well-established disease. Although some studies have shown that similar results are achieved with low-calorie diets (LCD’s) of 900 calories per day, the results are not usually sustained beyond three months.[16] Rates of type two diabetes are consistently reduced following surgery. A British meta-analysis demonstrated complete resolution of T2DM in 78.1% of patients and an average loss of 55% of the excess weight.[17]  

Analysis of over 50,000 patients in the UK National Bariatric Surgical Register revealed that mortality from bariatric surgery in hospitals is low (0.07%). The associated morbidity was 3.1%, and the most commonly encountered complications were post-operative vomiting, atelectasis/pneumonia, fever/infection, and electrolyte imbalance.[18] Bariatric surgery is associated with significant reductions in CVD, dyslipidemia, T2DM, obstructive sleep apnoea (OSA), arthritis, some cancers, fatty liver disease, and gastro-oesophageal reflux disease (GORD) from 1 year post-operatively. The benefit plateaus between 2 and 5 years postoperatively.

Although all patients should be recommended for surgical intervention on an individual basis in conjunction with the patient’s wishes, there is overwhelmingly statistically significant evidence of reducing overall mortality.[6]

Other Issues

Obesity is increasing on a global scale. The associated health concerns come with an increasingly global economic burden. In 2021, 73% of adults over 45 years old in England have a BMI greater than 25. The USA has the highest population rates of obesity globally, surpassing 40% for the first time. With the increasing demand for bariatric surgery comes greater pressure on specialist centers and teams. Patients with obesity require specialist equipment such as bariatric hospital beds, operating tables, and bariatric scanners. Bariatric surgery is a sub-specialty and requires specifically trained surgeons and working alongside appropriately qualified teams.

The cost of medical care for patients with obesity is around 30% greater than those with a normal BMI; this cost is higher still for those with a BMI > 35 where is around 81% greater. The median procedural costs from a nationwide American inpatient cohort were $9,219 for gastric band, $10,537 for SG, and $12,543 for gastric bypass. Despite these figures, even if revision surgery is required, bariatric surgery is cost-saving over an individual’s lifetime, compared with non-surgical management. In addition, there are indirect cost-savings associated with bariatric surgery, including less time off work and enhanced productivity.[19]

Enhancing Healthcare Team Outcomes

As mentioned previously, there is a large MDT involved in the care of patients undergoing bariatric surgery. This MDT is comprised of but is not limited to; surgeons, junior doctors, anesthetists, obesity medicine specialists, family Doctors, endocrinologists, gastroenterologists, psychiatrists, psychologists, diabetologists, nutritionists, dieticians, nurses, and physiotherapists, each with their own specialist areas of care and responsibility.

Achieving the best patient and team outcomes demands collaborative, cohesive, and efficient work between members of the MDT. Bariatric surgery is influenced by the key pillars of medical ethics; beneficence, non-maleficence, justice, and autonomy. At the center of the MDT is the patient, and their safety is always at the forefront of the care provided. An MDT that utilizes their individual skills and communicates effectively whilst working under the guidance of these ethical principles will have enhanced outcomes.