By Christina Frangou

In a major shift in policy, three major medical societies have changed their formal guidelines for bariatric surgery and expanded eligibility to include patients with mild to moderate obesity and diabetes or metabolic syndrome.

Additionally, the societies—the American Society for Metabolic and Bariatric Surgery, the American Association of Clinical Endocrinologists and the Obesity Society—upgraded sleeve gastrectomy from investigational status to a “proven surgical option.”


A 12-member panel recommends that patients with a body mass index of 30 to 34.9 kg/m2 and diabetes or metabolic syndrome may be offered a bariatric procedure.

Laparoscopic sleeve gastrectomy was added to the “proven” list of primary bariatric and metabolic procedures.

Laparoscopic procedures are preferred over open bariatric procedures due to lower early postoperative morbidity and mortality.

Emerging procedures such as gastric plication, electrical neuromodulation and endoscopic sleeves lack sufficient outcome evidence and remain investigational.

The changes will bring the U.S. guidelines in line with practices increasingly used around the country and reflect evidence that has emerged in the four years since the previous guideline was developed.

“We’ve gleaned important new insights, cautions and best practices based on the thousands of studies that were published in medical journals in just the last four years alone, and these are reflected in the new guidelines,” said Daniel B. Jones, MD, professor of surgery, Harvard Medical School, Boston, and one of a 12-member panel that developed the guidelines.

“Our goal was to make it a little easier for the practitioner to understand how strong the data are in favor of a practice, whether that be a psychological evaluation or a preoperative check of calcium and thiamine levels.”

The guidelines were published online March 25 in the journals of the three organizations: Endocrine Practice, Obesity and Surgery for Obesity and Related Diseases. They cover perioperative nutritional, metabolic and nonsurgical support for bariatric surgery patients.

Among the 74 evidence-based recommendations, the panel called for the broadening of surgical eligibility for bariatric surgery. Patients with a body mass index (BMI) of 30 to 34.9 kg/m2 and diabetes or metabolic syndrome may be offered a bariatric procedure, “although current evidence is limited by the number of subjects studied and lack of long-term data demonstrating a net benefit,” said the authors.

Two years ago, the International Diabetes Federation (IDF) was the first major organization to list surgery as a treatment option for patients with a BMI between 30 and 35 kg/m2 when diabetes cannot be adequately controlled by an optimal medical regimen.

Despite the IDF’s recommendation, the notion of surgery for individuals with a BMI of less than 35 kg/m2 has remained quite controversial, especially among physicians and endocrinologists, said Francesco Rubino, MD, a metabolic and bariatric surgeon at the Catholic University of Rome, Italy.

Dr. Rubino welcomes the new indication, saying the medical community must move away from a BMI cutoff for bariatric surgery.

“BMI per se does not measure health or disease. You never see a diabetologist, for instance, using BMI as a guide for diagnosis or treatment of diabetes.”

Dr. Jones said the guideline will make surgery accessible to people who are struggling with many comorbidities of obesity but do not meet the previous BMI threshold.

“As a bariatric surgeon and medical doctor, you hate to say to a patient, ‘you’re still too thin for surgery,’ especially when we know that the longer that they have diabetes, the more they weigh, the less likely that they will have a durable result.”

The panel noted that there is currently insufficient evidence for recommending a bariatric surgical procedure specifically for glycemic control alone, lipid lowering alone or cardiovascular disease risk reduction alone, independent of BMI criteria.

The panel also made a major addition to its list of “proven” primary bariatric and metabolic procedures by adding laparoscopic sleeve gastrectomy. The list now includes laparoscopic adjustable gastric banding, laparoscopic Roux-en-Y gastric bypass and laparoscopic biliopancreatic diversion (BPD), BPD/duodenal switch, along with laparoscopic sleeve gastrectomy.

The guidelines do not recommend one primary procedure over another. Each procedure poses different risks and benefits, the panel said, and surgeons should select a surgical method based on each patient’s goals and motivations and the surgeon and institution’s expertise and experience.

The authors did, however, observe that laparoscopic procedures are preferred over open bariatric procedures due to lower early postoperative morbidity and mortality, a finding supported by grade B evidence.

On the controversial issue of endoscopic and emerging bariatric procedures, the panel noted that other procedures are gaining attention, “such as gastric plication, electrical neuromodulation and endoscopic sleeves.” But, they said, these procedures lack sufficient outcome evidence and remain investigational.

The panel dropped 90 recommendations from the 2008 edition, revised 56 and added two. The quality of evidence improved significantly in the past five years, with 40.4% of studies now considered high quality compared with only 16.5% in the previous version.

In other new recommendations, the panel advised that women should avoid pregnancy before surgery and for 12 to 18 months after surgery. Women who do become pregnant after surgery should have nutritional surveillance and laboratory screening for deficiency every trimester, including iron, folate and B12, calcium and fat-soluble vitamins.

The guidelines also recommend that patients undergo age- and risk-appropriate cancer screening before surgery. “It’s really just good medicine. It may be obvious to screen for sleep apnea in a patient who is obese; cancer is maybe not as obvious. Now, we have data showing that the cancer rate may be higher with obesity, and bariatricians and internists really need to be screening for that,” said Dr. Jones.