By Charbel C. Khoury, MD
May 11, 2017
Obesity has grown at epidemic rates over the past few decades. According to the most recent data from the Behavioral Risk Factor Surveillance System, adult obesity prevalence now exceeds 35% in four US states, 30% in 25 states and is above 20% in all states.1 Numerous studies have established excess weight as a risk factor for type 2 diabetes, thus adding to the morbidity and mortality of obese patients. While dieting, behavioral approaches, and tight glucose control can limit the long-term complications of diabetes, sustaining adherence is often difficult for most patients.
Bariatric surgeries (Roux-en-Y gastric bypass, vertical sleeve gastrectomy, laparoscopic adjustable gastric banding, and biliopancreatic diversion) provide substantial weight loss and may reduce obesity-related complications. Recently, the Second Diabetes Surgery Summit (DSS-II) gathered the major diabetes organizations, and released a joint statement on the role of bariatric surgery.2 It recommended that clinicians consider bariatric surgery as an option in patients with class I obesity (BMI 30.0-34.9) if optimal medical treatment by oral or injectable medications inadequately controls their hyperglycemia.2
Indeed, evidence from observational and randomized controlled trials has been building in recent years. Most recently, Schauer et al. published the three-year and then the five-year outcomes of the STAMPEDE trial (Surgical Treatment and Medications Potentially Eradicate Diabetes Efficiently).3,4 This was a randomized, controlled, single-center study involving 150 obese patients. Intensive medical therapy was compared with gastric bypass or sleeve gastrectomy. The primary outcome was a glycated hemoglobin level (HbA1c) of 6.0% or less.
At enrollment, patients were 48±8 years old, 68% were women, the mean baseline glycated hemoglobin level was 9.3±1.5%, and the mean baseline BMI was 36.0±3.5. At 3 years, 38% of patients in the gastric-bypass group met the targeted HbA1c ≤ 6.0%, compared to only 5% of the patients in the medical-therapy group.4 This statistically significant difference was still notable at five years, with 29% of the gastric bypass, and 23% of the sleeve gastrectomy maintaining an HbA1c ≤ 6.0%.3
On average, patients who underwent surgical procedures had a mean percentage reduction in HbA1c of 2.1% at five years, and around 20% weight loss.3 Other secondary end points, including waist circumference, triglycerides, HDL cholesterol levels, also showed favorable results in the surgical groups, as compared with the group receiving intensive medical therapy alone.3
Overall, patients in the two surgical groups reported a better quality of life. Some adverse effects of surgical treatment were observed in this study, but they were modest in severity and relatively uncommon after the first year. There were no life-threatening operative complications or deaths in the surgical groups. Four patients required additional surgical interventions within the first 12 months after randomization, and one patient required a reoperation at four years. Mild anemia was more common in the two surgical groups than in the medical-therapy group. At five years, one patient in the medical-therapy group had a fatal myocardial infarction and one patient in the sleeve-gastrectomy group had a stroke.3
In conclusion, there is growing evidence that bariatric surgeries may have a potential role in the treatment of diabetic obese patients. However, further studies and a longer follow-up is needed to determine whether bariatric surgeries can decrease diabetic microvacular and macrovascular comorbidities, including cardiovascular disease. Since complications of bariatric surgery depend on the proficiency of the operating surgeon and ancillary services available, patients should preferably be referred to specialized centers with larger volumes. At this stage, the decision for bariatric surgery should be individualized to each patient. Those who decide to undergo surgery should understand the potential short and long-term risks, and commit to long term follow-up and monitoring to prevent the potential nutritional deficiencies.2
- The State of Obesity. 2016. (at http://stateofobesity.org/.)
- Brito JP, Montori VM, Davis AM. Metabolic Surgery in the Treatment Algorithm for Type 2 Diabetes: A Joint Statement by International Diabetes Organizations. JAMA 2017;317:635-6.
- Schauer PR, Bhatt DL, Kirwan JP, et al. Bariatric Surgery versus Intensive Medical Therapy for Diabetes – 5-Year Outcomes. N Engl J Med 2017;376:641-51.
- Schauer PR, Bhatt DL, Kirwan JP, et al. Bariatric surgery versus intensive medical therapy for diabetes–3-year outcomes. N Engl J Med 2014;370:2002-13.
Dr. Charbel C. Khoury is a renal fellow at the Brigham and Women’s and Massachusetts General Hospitals in Boston. He is also a Clinical Nutrition Fellow at the Brigham and Women’s Hospital.