Bariatric Surgery for Treatment of Type 2 Diabetes in Obese Patients: 3-Year Outcomes (STAMPEDE)

Summary

Of the more than 25 million Americans with type 2 diabetes mellitus (T2DM), fewer than half can attain adequate glycemic control. Bariatric surgery has resulted in improved glycemic and cardiovascular risk factor control in observational and short-term randomized studies, including the 1- year results of the Surgical Treatment and Medications Potentially Eradicate Diabetes Efficiently trial [STAMPEDE; Schauer P et al. N Engl J Med 2012]. The 3-year STAMPEDE data compared the effect of bariatric surgery with intensive medical therapy versus intensive medical therapy alone on glycemic control [Schauer PR et al. N Engl J Med 2014].

  • Obesity
  • Cardiology Clinical Trials
  • Interventional Techniques & Devices
  • Obesity
  • Diabetes Mellitus
  • Cardiology & Cardiovascular Medicine
  • Obesity
  • Cardiology Clinical Trials
  • Interventional Techniques & Devices
  • Diabetes Mellitus

Of the more than 25 million Americans with type 2 diabetes mellitus (T2DM), fewer than half can attain adequate glycemic control. Bariatric surgery has resulted in improved glycemic and cardiovascular risk factor control in observational and short-term randomized studies, including the 1- year results of the Surgical Treatment and Medications Potentially Eradicate Diabetes Efficiently trial [STAMPEDE; Schauer P et al. N Engl J Med 2012]. The 3-year STAMPEDE data, presented by Sangeeta R. Kashyap, MD, Cleveland Clinic, Cleveland, Ohio, USA, compared the effect of bariatric surgery with intensive medical therapy versus intensive medical therapy alone on glycemic control [Schauer PR et al. N Engl J Med 2014].

In the single-center trial, 150 patients aged 20 to 60 years with uncontrolled diabetes (HbA1C >7.0%) and body mass index (BMI) 27 to 43 kg/m2 were randomized to medical therapy alone (MT; n=50), MT plus laparoscopic Roux-en-Y gastric bypass (n=50), or MT plus laparoscopic sleeve gastrectomy (n=50). The MT regimen involved regular follow-up with extensive medication titration to achieve a target HbA1C of 6.0%. Subjects were encouraged to participate in a weight management program, such as Weight Watchers. The primary endpoint was the 3-year success rate in achieving HbA1C ≤6%. Secondary endpoints were changes in fasting plasma glucose (FPG), lipids, blood pressure, BMI, carotid intima media thickness (CIMT), medication usage, adverse events, and quality of life.

Thirteen patients (9%) were either lost to follow up (n=4) or withdrew consent (n=9), such that the 3-year analysis included 40, 48, and 49 patients in the MT alone, gastric bypass and sleeve gastrectomy arms, respectively. The three arms were comparable at baseline. The primary outcome, attainment of an HbA1C ≤6%, occurred in 5%, 38% and 24%, respectively, in the MT, gastric bypass, and sleeve gastrectomy arms with no significant differences between surgical arms (Table 1). Bariatric surgery also resulted in significant improvements in a number of secondary outcomes, including FPG, high-density lipoprotein, triglycerides, and medication usage. Both bariatric surgery approaches similarly reduced the percentage of patients on insulin, compared to MT alone. At 3 years, the percentage of patients requiring insulin in the MT, gastric bypass, and sleeve gastrectomy arm was 55%, 6%, and 8%, respectively. Requirement for cardiovascular medications was also substantially reduced by bariatric surgery. Only gastric bypass was associated with significantly diminished relapsed glycemic control compared with MT (Table 1).

Table 1.

Primary and Secondary Outcomes at 3 Years

Both types of bariatric surgery similarly and significantly decreased HbA1C at multiple time points throughout the 3-year trial (Table 2).

Table 2.

Change in HbA1C

Gastric bypass and sleeve gastrectomy also rapidly and significantly decreased BMI, and maintained the decrease over 3 years, compared with the modest reduction achieved with MT alone (p<0.001 for both), with gastric bypass proving significantly superior to sleeve gastrectomy from 6 months onward (p=0.006; Table 3).

Table 3.

Change in BMI

Adverse events were infrequent and similar between the study arms, with the exception of gastrointestinal complications, which occurred in 13 of 50 (26%) bypass patients.

The findings support bariatric surgery as a treatment option for moderately-to-severely obese patients with uncontrolled T2DM to improve glycemic control in the near-term. Longer follow-up of clinical results and larger experience in routine clinical practice will provide further insight into the durability of efficacy and the prognosis associated with adverse events with each of these bariatric surgery procedures.

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