Metabolic Surgery is Now a Recommended Treatment for Obese Patients with Type 2 Diabetes

New consensus guidelines for the treatment of type 2 diabetes mellitus (T2DM) recommend, for the first time, that metabolic surgery be recommended or considered as an intervention for many obese patients.

New consensus guidelines for the treatment of type 2 diabetes mellitus (T2DM) recommend, for the first time, that metabolic surgery be recommended or considered as an intervention for many obese patients.

A multidisciplinary group of 48 international clinicians and scholars (only 25% of whom were surgeons) gathered at the 2nd Diabetes Surgery Summit to review evidence from a decade’s worth of research and endorsed 32 conclusions about the use of surgery for T2DM patients. Those conclusions have, to date, been endorsed by 45 medical and scientific societies around the globe, including the American Diabetes Association, which just published the new guidelines in Diabetes Care.

The new guidelines say that surgery should be recommended to all T2DM patients with a body mass index (BMI) of at least 40 kg/m2 and to all patients with a BMI between 35 kg/m2 and 40 kg/m2 whose hyperglycemia is not controlled by lifestyle management and optimal medication.

Surgery should be considered, moreover, for hyperglycemic Asian patients with a BMI of at least 27.5 kg/m2 and all other hyperglycemic patients with a BMI of at least 30 kg/m2.

“Data from a growing number of recent randomized controlled trials in patients with T2DM, including mainly individuals with BMI ≥35 kg/m2 (the most commonly used threshold for traditional bariatric surgery) as well as some patients with BMI <35 kg/m2 (range 25—35 kg/m2), consistently demonstrate superior efficacy of bariatric/metabolic surgery in reducing weight and lowering glycemia compared with a variety of medical/lifestyle interventions,” the guideline authors wrote. “Our analysis of these trials shows a median HbA1c reduction of 2.0% for surgery versus 0.5% for conventional therapies (P < 0.001).”

The guideline authors also noted that several “classic” bariatric operations cause T2DM remission in a majority of all patients. Long-term follow-up information is relatively scarce, but it suggests that although 35% to 50% of all the patients who initially experience remission will eventually experience recurrence, a large percentage of patients remain free of the disease indefinitely. The median disease-free period for individual who undergo Roux-en-Y gastric bypass, for example, is 8.3 years.

Randomized trials have also shown that bariatric/metabolic surgery does better than medication-and-lifestyle regimens in reducing other risk factors for negative outcomes such as cardiovascular disease, but the guideline authors note that, to date, only non-randomized studies have observed actual reductions in the actual outcomes among surgery patients.

Surgery is expensive, of course, but existing research suggests that it is cost effective. Studies have generally put the cost per quality-adjusted life-year (QALY) for metabolic surgery between $3,200 and $6,300 — well below the $50,000 QALY threshold that is generally deemed sufficient for payer coverage.

“As a comparison, other treatments for diabetes, such as intensive glycemic and lipid control, have ICERs of $41,384/QALY and $51,889/QALY, respectively,” the guideline authors wrote. “Although some models have suggested that bariatric surgery may even be cost-saving, direct measurements of health care costs from clinical studies have not demonstrated that surgery decreases overall health care expenditures.”

Despite the general endorsement of metabolic surgery for certain patient groups, the new guidelines do acknowledge risks associated with surgery — both short-term complications and long-term nutritional deficiencies — as well as significant gaps in the research that demand further study.

“Available randomized controlled trials do not allow an assessment of the relative role of surgery versus conventional therapies in many clinical scenarios, including the long-term effects of the most commonly performed current procedure (VSG), or of the effectiveness of surgery in different stages of disease severity,” the guideline authors wrote.

“Further studies are needed to understand the roles of different operations in specific clinical scenarios, especially in adolescents and patients with BMI <35 kg/m2, and to determine what exactly constitutes failure of medical/lifestyle management before surgery is considered.”