Bariatric surgery


Bariatric surgery is a surgical procedure used to manage obesity and related conditions. Long-term weight loss with bariatric surgery may be achieved through alteration of gut hormones, physical reduction of stomach size, reduction of nutrient absorption, or a combination of these. Standard of care procedures include Roux en-Y bypass, sleeve gastrectomy, and biliopancreatic diversion with duodenal switch, from which weight loss is largely achieved by altering gut hormone levels responsible for hunger and satiety, leading to a new hormonal weight set point.
In morbidly obese people, bariatric surgery is the most effective treatment for weight loss and reducing complications. A 2021 meta-analysis found that bariatric surgery was associated with reduction in all-cause mortality among obese adults with or without type 2 diabetes. This meta-analysis also found that median life-expectancy was 9.3 years longer for obese adults with diabetes who received bariatric surgery as compared to routine care, whereas the life expectancy gain was 5.1 years for obese adults without diabetes. The risk of death in the period following surgery is less than 1 in 1,000. Bariatric surgery may also lower disease risk, including improvement in cardiovascular disease risk factors, fatty liver disease, and diabetes management.
Stomach reduction surgery is frequently used for cases where traditional weight loss approaches, consisting of diet and physical activity, have proven insufficient, or when obesity already significantly affects well-being and general health. The weight-loss procedure involves reducing food intake. Some individuals might suppress bodily functions to reduce the absorption of carbohydrates, fats, calories, and proteins. The outcome is a significant reduction in BMI. The efficacy of stomach reduction surgery varies depending on its specific type. There are two primary divisions, specifically gastric sleeve surgery and gastric bypass surgery.
the American Society of Metabolic and Bariatric Surgery and the International Federation for the Surgery of Obesity recommended consideration of bariatric surgery for adults meeting two specific criteria: those with a body mass index of more than 35 whether or not they have an obesity-associated condition and those with a BMI of 30–35 who have metabolic syndrome. However, these designated BMI ranges do not hold the same meaning in particular populations, such as among Asians, for whom bariatric surgery may be considered when a BMI is more than 27.5. Similarly, the American Academy of Pediatrics recommends bariatric surgery for adolescents 13 and older with a BMI greater than 120% of the 95th percentile for age and sex.

Medical uses

Bariatric surgery has proven to be the most effective obesity treatment option for enduring weight loss. Along with this weight reduction, the procedure reduces risk of cardiovascular diseases, type 2 diabetes, fatty liver disease, depression syndromes, among others. While often effective, numerous barriers to shared decision making between the medical provider and person affected include lack of insurance coverage or understanding how it functions, a lack of knowledge about procedures, conflicts with organizational priorities and care coordination, and tools supporting people who need the surgery.

Eligibility and guidelines

Historically, eligibility for bariatric surgery was defined as a BMI greater than 40, or a BMI more than 35 with an obesity-associated comorbidity, as based on the 1991 NIH Consensus Statement. In the three decades that followed, obesity rates continued to rise, laparoscopic surgical techniques made the procedure safer, and high-quality research showed effectiveness at improving health among various conditions. In October 2022, ASMBS/IFSO revised the eligibility criteria, which include all adult patients with a BMI greater than 35, and those with a BMI more than 30 with metabolic syndrome. However, BMI is a limited measurement, for which factors such as ethnicity are not used in the BMI calculation. Eligibility criteria for bariatric surgery are modified for people who identify as a part of the Asian population with a BMI of more than 27.5.
Stomach reduction surgeries were highly recommended for patients who meet these criteria: BMI>40, BMI>35, with specific comorbid conditions such as type 2 diabetes, hypertension, dyslipidemia, etc.
the American Academy of Pediatrics recommended bariatric surgery without age-based eligibility limits under the following indications: BMI more than 35 with severe comorbidity, such as obstructive sleep apnea, type 2 diabetes, idiopathic intracranial hypertension, nonalcoholic steatohepatitis, Blount disease, slipped capital femoral epiphysis, gastroesophageal reflux disease, and idiopathic hypertension or a BMI above 40 without comorbidities. Surgery is contraindicated with a medically correctable cause of obesity, substance abuse, concurrent or planned pregnancy, eating disorder, or inability to adhere to postoperative recommendations and mandatory lifestyle changes.
When counseling a patient on bariatric procedures, providers take an interdisciplinary approach. Psychiatric screening is also critical for determining postoperative success. People with a BMI of 40 or greater have a 5-fold risk of depression, and half of bariatric surgery candidates are depressed. Among bariatric surgery candidates and those who undergo bariatric surgery, mental health-related conditions including anxiety disorders, eating disorders, and substance use are also more commonly reported.

Age

Elderly patients will face higher postoperative complications due to frailty of elderly patients. The adolescents who performed stomach reduction surgery showed better results and there is no negative impact on linear/puberty growth.

Contraindications

Stomach reduction surgery is not suitable for people with the following conditions:
In adults, malabsorptive procedures lead to more weight loss than restrictive procedures, but they have a higher risk profile. Gastric banding is the least invasive, so it may offer fewer complications, while gastric bypass may offer the highest initial and most sustainable weight loss. A single protocol is not superior to the other. In one 2019 systematic review, estimated weight loss for each surgical protocol is as follows: 56.7% for gastric bypass, 45.9% for gastric banding, 74.1% for biliopancreatic bypass ± duodenal switch and 58.3% for sleeve gastrectomy. Most patients do remain obese following surgery despite significant weight loss, and patients with BMI over 40 tended to lose more weight than those with BMI under 40.
Concerning metabolic syndrome, bariatric surgery patients were able to achieve remission 2.4 times as often as those who underwent nonsurgical treatment. No significant difference was noted for changes in cholesterol, or LDL, but HDL did increase in the surgical groups, and reduction in blood pressure was variable between studies.

Type 2 diabetes mellitus

Studies of bariatric surgery for type 2 diabetes within the obese population show that 58% prioritize the improvement of diabetes, while 33% pursued surgery for weight loss alone. While weight loss is essential in T2DM management, sustaining improvements long-term is challenging; 50% to 90% of people struggle to achieve adequate diabetes control, suggesting the need for alternative interventions. In this context, studies have reported an 85–90% resolution of T2DM after bariatric surgery, measured by reductions in fasting plasma glucose and HbA1C levels, and remission rates of up to 74% two years post-surgery. Bariatric surgery is considered for individuals with new-onset T2DM and obesity, although the level of improvement may be slightly less.
The relative risk reductions associated with bariatric surgery are 61%, 64%, and 77% for the development of T2DM, hypertension, and dyslipidemia, respectively, highlighting the efficacy of bariatric surgery in prevention as well as resolution of chronic obesity. Predictors for post-operative diabetes resolution include the current method of diabetes control, adequate blood sugar control, age, duration of diabetes, and waist circumference.
Bariatric surgery likewise plays a role in the reduction of medication use. During postoperative follow-up, 76% of people discontinued the use of insulin, while 62% no longer required T2DM medications at all.

Reduced mortality and morbidity

A 2021 meta-analysis found that bariatric surgery was associated with 59% and 30% reductions in all-cause mortality among obese adults with or without type 2 diabetes respectively. It also found that median life expectancy was 9 years longer for obese adults with diabetes who received bariatric surgery as compared to routine care, whereas the life expectancy gain was 5 years longer for obese adults without diabetes. The overall cancer risk in bariatric surgery patients was decreased by 44%, especially in colorectal, endometrial, breast, and ovarian cancer. Improvements in cardiovascular health are the most well-described changes after bariatric surgery, with notable reductions in the incidence of stroke, heart attack, atrial fibrillation, all-cause cardiovascular mortality, and ischemic heart disease.
Bariatric surgery in older patients is a safety concern; the relative benefits and risks in this population are not known.

Fertility and pregnancy

In 2017, the American Society for Metabolic and Bariatric Surgery stated that it was not clear whether medical weight-loss treatments or bariatric surgery affected subsequent treatments for infertility in both men and women.
Bariatric surgery reduces the risk of gestational diabetes and hypertensive disorders of pregnancy in women who later become pregnant, but increases the risks of preterm birth and maternal anemia. A 2021 systematic review found that post-bariatric surgery normalized hormonal levels and menstrual cycles, and improved fertility, with no increased short-term risk of miscarriages or congenital malformations.
For women with polycystic ovary syndrome, post-operatively there tends to be a reduction in menstrual irregularity, hirsutism, infertility, and the overall prevalence of polycystic ovary syndrome is reduced by bariatric surgery at 12 and 23 months.