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Surgical Procedures for Obese Patients with Type 2 Diabetes
Obese patients with type 2 diabetes are commonly prescribed medications and are further encouraged to exercise and improve their diets. In recent years, however, Roux-en-Y gastric bypass surgery, laparoscopic adjustable gastric banding (LAGB), and sleeve gastrectomy are becoming more popular options for obese patients.
Several studies have evaluated the safety and efficacy of surgical procedures in helping patients lose weight and control hemoglobin A1c (HbA1c) and other factors associated with type 2 diabetes. Three articles published so far this year have shown the benefits of surgery, but they have also indicated some limitations, including the difficulty in conducting a large, randomized trial in this patient population. Here, First Report Managed Care provides an overview of each study.
3-Year Outcomes Study
After 3 years of treatment, 38% of obese patients with type 2 diabetes who underwent intensive medical therapy and bariatric surgery had an HbA1c level of ≤6% compared with 5% of patients who only had the medical therapy (P<.001), according to a randomized trial. In addition, 24% of patients who underwent sleeve gastrectomy had an HbA1c level of ≤6%, which was significantly higher than the results of the medical therapy group (P<.001).
The study’s results were presented at the American College of Cardiology Scientific Session in March and published in New England Journal of Medicine [2014;370(21):2002-2013]. Ethicon, LifeScan, the Cleveland Clinic, and the National Institutes of Health (NIH) supported the study.
The STAMPEDE (Surgical Treatment and Medications Potentially Eradicate Diabetes Efficiently) trial included 150 obese patients who were randomized in a 1:1:1 ratio to receive medical therapy or undergo gastric bypass or sleeve gastrectomy. Randomization occurred from March 2007 through January 2011.
Patients were eligible if they were 20 to 60 years of age, had an HbA1c level >7%, and a body mass index (BMI) of 27 kg/m2 to 43 kg/m2. Of the patients included, 68% were women and 74% were white. The mean age was 48 years, the mean BMI was 36 kg/m2, the mean HbA1c level was 9.3%, and the mean duration of diabetes was 8.3 years.
Of the patients in the medical therapy group, 80% had a glycemic relapse compared with 24% in the gastric bypass group (P=.03) and 50% in the sleeve gastrectomy group (P=.34). The authors defined a glycemic relapse as a patient who had an HbA1c level of ≤6% at 1 year but not at 3 years.
After 3 years, the median fasting plasma glucose (FPG) level decreased 6 mg/dL in the medical therapy group, 85.5 mg/dL in the gastric bypass group, and 46 mg/dL in the sleeve gastrectomy group. During that same time period, the mean body weight reduction was 4.2% in the medical therapy group, 24.5% in the gastric bypass group, and 21.1% in the sleeve gastrectomy group.
There were some study limitations, according to the authors. They noted that there was “an inadequate sample size and duration to detect differences in the incidence of diabetes complications, such as myocardial infarction, stroke, or death.” All patients will be followed-up again after 5 years.
1-Year Randomized Trial
One year after treatment, 58% of patients with type 2 diabetes who underwent gastric bypass surgery had an HbA1c level <6.5% and a FPG level <126 mg/dL compared with 16% of patients who enrolled in a medical management program, according to a randomized, parallel-group, pragmatic trial. The results were statistically significant (P=.03), and the study was published in JAMA Surgery [2014; DOI:10.1001/jamasurg.2014.514].
The SLIMM-T2D (Surgery or Lifestyle with Intensive Medical Management in the Treatment of Type 2 Diabetes) trial included patients who were 21 to 65 years of age, had type 2 diabetes for at least 1 year, had a BMI from 30 kg/m2 to 42 kg/m2, and did not have any diseases prohibiting them from exercising or undergoing surgery.
Patients were randomized to undergo gastric bypass surgery or enroll in the medical management program. If they were in the former group, they had the procedure performed at Brigham and Women’s Hospital in Boston, Massachusetts. If they were in the latter group, they participated in the Why WAIT (Weight Achievement and Intensive Treatment) program that based its cognitive behavioral support on the Diabetes Prevention Program (DPP) and the Look AHEAD (Action for Health in Diabetes) study.
The Why WAIT program, however, differed from the ones used in DPP and Look AHEAD in its medical adjustment plan, caloric reduction and dietary composition, exercise type and duration, and diabetes education sessions. The Why WAIT program included groups of 15 to 20 patients who met with an endocrinologist, registered dietician, exercise physiologist, mental health provider, and certified diabetes nurse educator. Participants had weekly medication adjustments, a structured diet, up to 300 minutes per week of exercise with an emphasis on strength training, cognitive behavioral intervention, and group education.
From March 12, 2010, to September 7, 2011, the authors spoke with 822 people via telephone. They eventually randomized 43 patients to undergo gastric bypass surgery (n=22) or to participate in the Why WAIT program (n=21).
All patients who underwent gastric bypass surgery lost at least 10% of their weight before 3 months compared with 37% of patients in the Why WAIT group. The authors noted that patients in the surgery group also had greater reductions in waist circumference, fat, and lean mass.
Both groups had a significant reduction in HbA1c level from baseline at 3 months, but the difference was not significant. However, after 1 year, patients who underwent gastric bypass surgery had a significantly greater HbA1c reduction from baseline, while patients who were in the Why WAIT program did not maintain their HbA1c decrease. At 1 year, patients in the surgery group also had greater reductions in the estimated cardiometabolic risk scores for coronary heart disease (CHD), fatal CHD, stroke, and fatal stroke.
Study limitations included that the duration of diabetes and insulin use varied among patients. The authors also noted that they could not assess infrequent or long-term adverse events, cardiovascular or mortality outcomes, or cost-effectiveness because there were only a small number of participants.
Feasibility Study
A single-arm, randomized, controlled, feasibility study found that there were numerous potential obstacles to completing larger trials for obese patients with type 2 diabetes and a BMI of 30 kg/m2 to 40 kg/m2. The authors noted that it was difficult to recruit and retain participants.
However, they found that obese patients with type 2 diabetes who underwent gastric bypass surgery had a greater mean weight loss and partial disease remission compared with patients who had a LAGB procedure or enrolled in an intensive lifestyle weight loss intervention. Preliminary results were published in JAMA Surgery [2014; DOI:10.1001/jamasurg.2014.467].
Previous trials showed that grade 2 or 3 patients undergoing bariatric surgery lost weight and controlled obesity-related type 2 diabetes, but the authors in this study noted that long-term outcomes associated with the procedure were still unknown, particularly for patients with grade 1 obesity. The authors also said large, multicenter, randomized trials are costly, time-consuming, and difficult to execute.
This study was among 7 prospective pilot and feasibility studies funded by NIH. It was modeled after the Look AHEAD study and was conducted at the University of Pittsburgh Medical Center from October 1, 2009, through May 31, 2012.
Patients were eligible to enroll if they were 25 to 55 years of age, had a BMI of 30 kg/m2 to 40 kg/m2, and had type 2 diabetes. They were excluded if they had prior weight loss surgery, impaired mental status, alcohol or drug addiction, were a current smoker, or were pregnant or planned to get pregnant.
Patients who underwent gastric bypass surgery had follow-up visits at 2 weeks and again at 3, 6, 9, and 12 months following the operation, while patients in the LAGB group had follow-up visits at 2 weeks and again at 2, 4, 6, 8, 10, and 12 months following the procedure. Both groups were encouraged to exercise at least 3 to 4 times per week and to diet based on post-surgery recommendations.
The lifestyle weight loss intervention was based on the DPP and the Look AHEAD trials. For the first 6 months, patients in the lifestyle group had weekly in-person sessions. For months 7 to 12, the weekly sessions were held in-person on the first and third weeks of the month and were conducted via telephone in weeks 2 and 4. They were asked to self-monitor their body weight, eating, and exercise and were told to exercise 5 days per week beginning at 20 minutes per day and increasing to 60 minutes per day.
Only 69 of the 667 patients who were screened met the eligibility requirements and were randomized. The mean age of the randomized patients was 47.3 years, the mean BMI was 35.6 kg/m2, the mean HbA1c level was 7.9%, and the mean duration of type 2 diabetes at baseline was 6.4 years.
Patients in the gastric bypass group had a 27% mean reduction in body weight from baseline compared with a decrease of 17.3% in the LAGB group and 10.2% in the lifestyle weight loss intervention group. At 12 months, partial remission of type 2 diabetes was found in 50% of the patients undergoing gastric bypass and 27% of patients undergoing LAGB, while complete remission was found in 17% and 23% of patients, respectively.
