In 2008, the Obesity Society, the American Association of Clinical Endocrinologists, and the American Society for Metabolic & Bariatric Surgery published a joint clinical practice guideline on the perioperative nutritional, metabolic, and non-surgical support of bariatric surgery patients. Since that time, a significant increase in the amount and strength of data has emerged. In 2013, the guidelines were updated to reflect these changes.

Key Changes to the Bariatric Surgery Guideline

For the 2013 updated guidelines, experts revised 56 of the 72 recommendations that were made in the 2008 document and added just two. These revisions represent such changes as the FDA approval of sleeve gastrectomy, which was considered an investigative procedure in 2008, says Jeffrey I. Mechanick, MD, FACP, FACE, FACN, ECNU, who served as lead author of the updated guideline that was published in Endocrine Practice, Surgery for Obesity and Related Diseases, and Obesity.

Over the past 5 years, the role of bariatric surgery in patients with type 2 diabetes has become clearer, says Dr. Mechanick. “We still are not recommending bariatric surgery for patients with diabetes who are not obese. Instead, bariatric surgery should be considered in patients with diabetes who are obese and who have not responded to conventional methods for controlling their disease.”


The use of bariatric surgery in patients with mild obesity was a new addition to the guideline. With the FDA approval of the Lap-Band® (Apollo Endosurgery, Inc) device for patients with mild obesity, the expert writing committee made the recommendation for considering gastric banding in select patients with a BMI of 30 kg/m2 to 35 kg/m2 and at least one obesity-related comorbidity.

Helpful Checklists for Physicians

Another new addition to the guideline update is the inclusion of checklists. “Research in multiple industries, including medicine, shows that checklists can help prevent near misses,” explains Dr. Mechanick. “The preoperative checklist for bariatric surgery [Table] includes items that might not be at the top of physicians’ minds, such as cancer screening, obtaining routine labs, and nutrient screening. These items are important because many bariatric surgery patients enter the procedure already deficient in
many nutrients.”

Cardiopulmonary evaluation with sleep apnea screening is also included in the preoperative checklist, despite ongoing debate over the extent to which sleep apnea screening should be performed in this setting. Dr. Mechanick notes that endocrine evaluations should be specifically focused on diabetes, as well as polycystic ovary syndrome in women. The preoperative checklist also includes practices to avoid, such as screening all obese patients with a thyroid-stimulating hormone level. “The data don’t support this practice unless patients are suspected of having hypothyroidism or if their insurance company mandates it,” adds Dr. Mechanick.

For the postoperative checklist, separate columns for checkmarks and frequency of follow-up were used. This was done because some patients who have undergone laparoscopic adjustable gastric banding, for example, may not be as high risk as those who have undergone biliopancreatic diversion, explains Dr. Mechanick. “The key is for clinicians to consider all of the variables depending on each individual patient. These checklists can help guide the way.”

Addressing Nutritional & Metabolic Needs

The recommendations made in the guidelines on nutritional and metabolic needs of bariatric surgery patients are extensive. “Providers need to drill down, identify, and parse out the individual types of nutrition and metabolic issues, such as metabolic bone disease,” says Dr. Mechanick. Obese patients tend to undergo bariatric surgery already having vitamin D insufficiency or deficiency. Bone density tends to decrease following the surgery, but a new diagnosis of osteoporosis should not be made for 1 to 2 years, according to Dr. Mechanick. However, vitamin D should be provided to patients who have difficulty absorbing a sufficient amount of vitamin D.

Protein is another important consideration, says Dr. Mechanick. “Patients who undergo biliopancreatic diversion should receive 60 g to 120 g of protein per day to avoid hypoalbuminemia,” he adds. “Only about 5% of patients who undergo Roux-en-Y procedures become protein deficient, perhaps from developing a distorted sense of taste and then choosing to not eat much meat.”

A Focus on Team Approaches

According to the guideline update, a team approach to perioperative care is mandatory for bariatric surgery patients. “Team members should be managing the nutritional and metabolic components of bariatric surgery before and during operative care,” says Dr. Mechanick. “The mainstay for obesity therapy should be lifestyle management and medicine. Bariatric surgical patients require the care of a multidisciplinary team that can track weight loss, screen for complications, and understand their patients’ unique metabolic and nutritional needs. With this team approach, bariatric surgery can continue to be a safe and effective intervention in the comprehensive management of select patients with obesity.”