People with diabetes and severe obesity who had metabolic surgery were much less likely to die from diabetes or any other cause than those who received drug therapy alone, according to a new meta-analysis by German researchers who presented their findings* today at ObesityWeek℠ 2018, the largest international scientific conference focused on the prevention and treatment of obesity hosted by the American Society for Metabolic and Bariatric Surgery (ASMBS)and The Obesity Society (TOS).

Based on an analysis of 19 studies – six randomized controlled trials and 14 clinical trials published between 1997 and 2017 – 66 percent fewer metabolic surgery patients died than patients who received standard medical therapy for their diabetes. Patients were also 62 percent less likely to suffer a heart attack or stroke, although the duration of diabetes reduced the effect of metabolic surgery on the incidence of these macrovascular complications. The average body mass index (BMI) was 42 in the surgery group and BMI 40 in the medical therapy group.

"This analysis shows metabolic surgery is the only therapy that beneficially affects all diabetes-related complications, at the same time resulting in fewer deaths and cardiovascular events," said Adrian T. Billeter, MD, PhD, lead study author from the University of Heidelberg in Germany. "The majority of diabetes medications do not have such an effect, so the case for metabolic surgery is very compelling."

In another meta-analysis published earlier this year in the British Journal of Surgery, Billeter and colleagues reported that metabolic surgery was also superior to medical therapy, by as much as 74 percent, in preventing the development of microvascular complications including diabetic nephropathy, neuropathy, and retinopathy in patients with type 2 diabetes and severe obesity.

According to the American Diabetes Association, more than 30 million Americans or 9.4 percent of the population have type 2 diabetes, which is the 7th leading cause of death in the United States. ₁ Two out of three people with diabetes die from heart disease or stroke. ₂ The World Health Organization estimates 90 percent of people with the disease are overweight or have obesity.₃

"This study adds to the enormous amount of data demonstrating the profound and definitive effect of metabolic surgery on obesity, diabetes and its complications that no other therapy can achieve, yet surgery remains vastly underutilized as a treatment," said Samer Mattar, MD, president, ASMBS and medical director at Swedish Weight Loss Services in Seattle, Washington, who was not involved in the study. "While metabolic surgery is certainly not for everyone – there are many factors to consider – many are missing out on a transformational procedure."

The Centers for Disease Control and Prevention (CDC) reports 93.3 million or 39.8 percent of adults in the U.S. had obesity in 2015-2016. ₄ The ASMBS estimates about 24 million have severe obesity, which for adults means a BMI of 35 or more with an obesity-related condition like diabetes or a BMI of 40 or more. In 2017, 228,000 bariatric procedures were performed in the U.S., which is about 1 percent of the population eligible for surgery based on BMI.

Metabolic/bariatric surgery has been shown to be the most effective and long-lasting treatment for severe obesity and many related conditions and results in significant weight loss. ₅ The Agency for Healthcare Research and Quality (AHRQ) reported significant improvements in the safety of metabolic/bariatric surgery due in large part to improved laparoscopic techniques. ₆ The risk of death is about 0.1 percent ₇ and the overall likelihood of major complications is about 4 percent. ₈ According to a study from the Cleveland Clinic's Bariatric and Metabolic Institute, laparoscopic bariatric surgery has complication and mortality rates comparable to some of the safest and most commonly performed surgeries in the U.S., including gallbladder surgery, appendectomy and knee replacement. ₉

About the ASMBS

The ASMBS is the largest organization for bariatric surgeons in the nation. It is a non-profit organization that works to advance the art and science of bariatric surgery and is committed to educating medical professionals and the lay public about bariatric surgery as an option for the treatment of severe obesity, as well as the associated risks and benefits. It encourages its members to investigate and discover new advances in bariatric surgery, while maintaining a steady exchange of experiences and ideas that may lead to improved surgical outcomes for patients with severe obesity. For more information, visit www.asmbs.org.

*Metabolic surgery reduces mortality and macrovascular complications in patients with type 2 diabetes mellitus compared to medical therapy: a meta-analysis (A136)

Adrian T. Billeter, MD, PhD, Sebastian Eichel, Medical Student, Katharina Scheurlen, MD, Stefan Kopf, MD, Pascal Probst, MD, Beat P. Müller-Stich, MD, all from the University of Heidelberg, Germany

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