Lifestyle modifications and medication therapy are the mainstay in the treatment of type 2 diabetes. Many diabetes medications can potentially increase weight including insulin, sulfonylureas, meglitinides, and thiazolidinediones.1 With an estimated 56.9% of adult diabetics overweight/obese2, these medications can hinder weight-loss efforts made by patients. Current American Diabetes Association (ADA) guidelines indicate that bariatric surgery can be considered for type 2 diabetic patients with a body mass index (BMI) greater than 35 kg/m2, particularly if the diabetes and/or comorbidities are difficult to control with lifestyle changes and medication therapy.3 However, little research is available on the efficacy, safety and long-term benefits of bariatric surgery in patients with type 2 diabetes. Comparisons with current medication therapies will better define the role of bariatric surgery in type 2 diabetics as well as determine the efficacy and safety in this patient population.
Schauer and colleagues compared the efficacy of intensive medical therapy alone versus medical therapy plus Roux-en-Y gastric bypass or sleeve gastrectomy in obese patients with Type 2 diabetes in a randomized, non-blinded, single-center, controlled trial titled STAMPEDE (Surgical Treatment and Medications Potentially Eradicate Diabetes Efficiently). Patient were included if they were between the ages of 20-60, had a diagnosis of Type 2 diabetes (A1C >7%) and a BMI of 27-43.
Eligible patients were assigned to one of three treatment arms in a 1:1:1 ratio to: (1) intensive medical therapy (medical therapy to a goal A1C <6% or medication intolerant), (2) intensive medical therapy plus Rou-en-Y, and (3) intensive medical therapy plus sleeve gastrectomy.4 Intensive medical therapy for all groups included lifestyle counseling, weight management, frequent home glucose monitoring and use of FDA-approved medications. All patients were treated with lipid-lowering and antihypertensive agents per ADA guidelines. The primary endpoint was the proportion of patients with A1C <6% (with or without diabetes medications) twelve months after randomization. Secondary endpoints included fasting plasma glucose, fasting insulin, lipids and high-sensitivity C-reactive protein (CRP), homeostasis model assessment of insulin resistance (HOMA-IR) index, weight loss, blood pressure, adverse events, coexisting illnesses and changes in medications.4
A total of 150 patients were eligible and 93% completed the 12 month follow-up. There was no difference among baseline characteristics. Patients had a mean age of 49±8 years, 66% were female, the average duration of diabetes was more than 8 years, and 44% were using insulin at baseline. The average baseline A1C was 9.2±1.5% and the BMI was 36 with 34% of individuals having a BMI <35. At 12 months, glycemic control improved in all groups, but the surgical groups had a greater improvement. For the primary endpoint, less patients in the medical therapy group (12%) were at the target A1C versus the gastric bypass (42%, P=0.002) and sleeve gastrectomy groups (37%, P=0.008); there was no significant difference between the surgical groups. All of the gastric bypass patients and 28% of the patients in the sleeve gastrectomy group that achieved the primary endpoint without medications. Changes in body weight, waist circumference and waist-to-hip ratio were greater in both surgical groups than medical therapy alone; in addition weight and BMI changes were greater with gastric bypass than sleeve gastrectomy (P=0.02 and 0.03, respectively). Significant decrease in triglycerides occurred in the gastric bypass group, and HDL increased and high-sensitivity CRP level decreased in the surgical groups. Medications needed for treating hyperlipidemia and hypertension decreased in the surgical groups. There were no significant differences for total and LDL cholesterol or systolic/diastolic blood pressure values. There were no deaths or serious episodes of hypoglycemia among the three groups. Adverse events included additional surgical intervention in four patients.4
This study showed that younger patients with more severe, poorly controlled diabetes who underwent either surgical procedure combined with medical therapy were significantly more likely to achieve an A1C <6% at twelve months and reach more favorable results toward the secondary endpoints. While these results are impressive, the role of bariatric surgery in the treatment of type 2 diabetics remains uncertain. Will the favorable secondary outcomes such as decreased need for cardiovascular medications and decreased metabolic syndrome translate to reduced diabetes associated complications such as retinopathy, nephropathy, neuropathy and cardiovascular disease? It is unknown at this time if these favorable outcomes will slow or perhaps stop the progression of diabetes and if the positive results can be maintained long-term. In deciding if bariatric surgery is an appropriate choice, one should remember that surgery is not without its risks and that there are lifelong changes that must be made with bariatric surgery, such as vitamin supplementation and eating habits. Limitations for this trial include the one center setting and its short duration (a 4-year extension study is planned). More studies using multiple centers over longer duration will further clarify the role that bariatric surgery can have in the treatment of type 2 diabetes as well as the long-term benefits and risks of the surgery. For now, the surgery is best reserved for younger patients with a long duration of severe disease who have failed to reach therapeutic goals despite intensive medical therapy combined with the appropriate lifestyle modifications.
1. Triplitt CL, Reasner CA. Chapter 83. Diabetes Mellitus. In: Talbert RL, DiPiro JT, Matzke GR, Posey LM, Wells BG, Yee GC, eds. Pharmacotherapy: A Pathophysiologic Approach
. 8th ed. New York: McGraw-Hill; 2011. http://www.accesspharmacy.com/content.aspx?aID=7990956
. Accessed June 21, 2012.
3. American Diabetes Association. Standards of Medical Care in Diabetes-2012. Diabetes Care.
2012 Jan;35 Suppl1:S11-63.
4. Schauer PR, Kashyap SR, Wolski ...