2022 AMERICAN SOCIETY FOR METABOLIC AND BARIATRIC SURGERY (ASMBS) AND INTERNATIONAL FEDERATION FOR THE SURGERY OF OBESITY AND METABOLIC DISORDERS (IFSO):

INDICATIONS FOR METABOLIC AND BARIATRIC SURGERY

The concept of pandemic has entered our lives due to the recent emergence and ongoing effects of the coronavirus outbreak. A pandemic is defined as a general term for epidemic diseases that spread across multiple countries or continents. Obesity can be considered a pandemic as it is a disease affecting the entire world and spreading across vast areas.

Obesity is not merely a cosmetic issue but a serious disease. It harbors severe conditions that each shorten life expectancy. Although bariatric and metabolic surgeries (BMS) are prominently highlighted on social media and other platforms for their cosmetic results, our main goal as physicians is to treat the diseases associated with obesity through weight loss. This distinction is important and open to debate from an ethical standpoint.

As physicians, we have been fighting against obesity for many years. Based on our current knowledge, the most effective treatment for obesity is surgery. Thirty years ago, the National Institutes of Health (NIH) in the United States published a consensus statement on the fight against obesity. Despite all efforts over the past 30 years, the obesity pandemic could not be halted, and increases in the number of obese patients worldwide have been observed.

Thirty years later, the American Society for Metabolic and Bariatric Surgery (ASMBS) and the International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) published international guideline recommendations.

These guidelines include changes in the indications for bariatric and metabolic surgery and many other areas compared to the NIH consensus statement.

CRITERIA FOR SURGERY:

BMI (Body Mass Index) kg/m²:

BMI is the most appropriate and widely used criterion for identifying and classifying overweight or obese patients. BMS is currently the most effective evidence-based treatment for obesity across all BMI classes.

In the NIH consensus statement, surgery was recommended for patients with a BMI >35 kg/m² who had obesity-related diseases, regardless of whether they had comorbidities. The new guidelines state that:

In Class 1 obesity patients with a BMI between 30-35 kg/m², a trial of non-surgical treatment is recommended. However, BMS is recommended for appropriate individuals with obesity and type 2 diabetes, hypertension, dyslipidemia, obstructive sleep apnea, cardiovascular disease (e.g., coronary artery disease, heart failure, atrial fibrillation), asthma, fatty liver disease and non-alcoholic steatohepatitis (liver steatosis), chronic kidney disease, polycystic ovary syndrome, infertility, gastroesophageal reflux disease, pseudotumor cerebri, and bone and joint diseases.

In patients with a BMI >35 kg/m², BMS is strongly recommended, regardless of the presence of obesity-related diseases.

In the Asian population, surgery should be considered when the BMI reaches 27.5 kg/m².

AGE:

Advanced Age: There is insufficient data to determine an age limit. Decisions should be made based on comorbidities and the patient’s overall condition. Evidence exists that suitable patients in older age groups benefit from BMS and that the procedures can be performed safely.

Pediatric Patients and Adolescents: BMS is safe for the adolescent group under 18 years old. Contrary to popular belief, BMS does not adversely affect growth and pubertal development.

For the pediatric group, BMS is recommended for children/adolescents with a BMI >120% of the 95th percentile (Class II obesity) and major comorbidities or a BMI >140% of the 95th percentile (Class III obesity). No lower age limit is specified.

BRIDGE FOR OTHER TREATMENTS:

Arthroplasty: It is suggested that the BMI be below 40 for patients undergoing major joint surgeries. Patients operated on with a low BMI have lower rates of complications and higher success rates for treatment. Therefore, BMS can be considered as a bridging procedure prior to major joint surgeries.

Abdominal Wall Hernias: Obesity is a risk factor for the formation of abdominal wall hernias due to increased intra-abdominal pressure. Hernia repairs in obese individuals may predispose them to wound infections, recurrence, and other complications. Weight loss prior to hernia repair in obese patients with large abdominal wall hernias will reduce complication and recurrence rates. Therefore, BMS should be considered before hernia repair in these patients.

Organ Transplantation: Obesity is a risk factor for end-stage organ failure (liver failure, kidney failure, etc.). Obesity may contraindicate organ transplantation from a metabolic and technical perspective. Therefore, access to organ transplantation may be limited for obese individuals. BMS has been defined as a way to improve candidacy for transplantation in patients with end-stage organ disease. Patients with end-stage organ disease may achieve significant weight loss and improve their eligibility for organ transplantation.

BMS in High-Risk Patients: Patients with a high BMI are considered high-risk for surgery due to a higher incidence of comorbidities. However, studies have shown that BMS can be safely performed even in patients with a BMI >70 kg/m². Therefore, BMS should be considered as a preferred method for patients with excessive BMI.

In addition, improvements in early-stage liver cirrhosis and cardiac function have been shown following weight loss with BMS. BMS may be recommended in suitable patients to halt the progression of such diseases and achieve recovery.

The 1991 NIH Consensus Statement recommended that patients who are candidates for BMS be evaluated by a multidisciplinary team. This view remains valid today. Studies have shown that evaluating patients preoperatively by a multidisciplinary team can reduce complication rates. There is no scientific data regarding the necessity or priority of weight loss before surgery. This process may lead to delays in treatment for an obese patient due to comorbidities. Preoperative multidisciplinary assessment can manage preventable risk factors and reduce complication rates, but the decision to proceed with surgery should be determined by the surgeon.

Postoperative nutrition is crucial. It is recommended that a dietitian with experience evaluate the patient preoperatively and follow up postoperatively as part of the multidisciplinary team. Psychological support is also recommended to cope with changes in body image and lifestyle alterations following weight loss.

In Conclusion:

BMS are effective and reliable surgeries for treating severe obesity and comorbid conditions. Compared to non-surgical treatment methods, they lead to a decrease in mortality rates due to diseases associated with obesity.

For patients with a BMI >35 kg/m², regardless of the presence of comorbidities;

For patients with a BMI >30 kg/m² and type 2 diabetes;

For patients with a BMI between 30-35 kg/m² who have not achieved sustained weight loss or improvement in comorbid conditions through non-surgical methods, BMS should be considered.

In the Asian population, the obesity threshold should be considered as a BMI of 25 kg/m², and BMS should be considered for patients with a BMI >27.5 kg/m².

There is no upper age limit for BMS. They can be performed in suitable patients based on their comorbidities and risk status.

BMS can be safely performed in pediatric and adolescent age groups. Surgery can be recommended for patients evaluated and deemed appropriate by experienced centers and multidisciplinary teams.

In patients with severe obesity, BMS may be considered as a bridging therapy for special surgeries such as major joint surgeries, abdominal wall hernia repairs, or organ transplantation.

The decision for surgery should be determined by the surgeon. Preoperative multidisciplinary assessment can help manage preventable risk factors and reduce complication rates.

Source: 2022 American Society for Metabolic and Bariatric Surgery (ASMBS) and International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO): Indications for Metabolic and Bariatric Surgery