Bariatric Surgery Indicated in Obese Patients with Type 2 Diabetes

In an unblinded randomized trial conducted from December 2002 through December 2006 at the Center for Obesity Research and Education (CORE) of Monash University (Melbourne, Australia), Dr. John B. Dixon and colleagues recruited 60 obese patients with type 2 diabetes diagnosed within a two year period from the start of the study, and randomly assigned them into two treatment groups. The first group received conventional diabetes therapy focused on lifestyle changes and weight loss. The second group underwent laparoscopic adjustable gastric banding (LAGB) surgery (within one month of randomization) and in addition received conventional diabetes care. Patients in the surgery group had their progress reviewed every four to eight weeks and had their gastric band volume adjusted as needed.

The patients studied were between the ages of 20 and 60 (average age 47), with a body mass index (BMI) >30 and <40 kg/m2, and no evidence of renal impairment or retinopathy. Exclusions from the study were based on previous bariatric surgery, type 1 diabetes, or vascular events. Each patient was assessed by a dietitian, a general physician, and an endocrinologist.

The principal outcome measures were the remission of type 2 diabetes defined as fasting glucose levels of less than 126 mg/dL and glycated hemoglobin (HbA1c) value less than 6.2% without glycemic therapy. Other outcome measures were patient weight and metabolic syndrome components such as abdominal obesity.

Of the 60 patients enrolled in the study, 55 (92%) completed the 2-year follow-up. Diabetes remission was achieved for 22 (73%) of patients in the surgical group and for four (13%) in patients who received conventional therapy. Remission of type 2 diabetes was associated with weight loss and lower starting HbA1c levels. The surgical group achieved a mean body weight loss of 20% after two years (corresponding to a drop in BMI from 36.9 to 29.5 kg/m2), while patients receiving conventional therapy lost 1.4% of body weight (a drop in BMI from 37.1 to 36.6 kg/m2). Compared with patients in the conventional therapy group, those in the surgery group also achieved an improved lipid profile at the two-year mark with reductions in triglycerides, increased HDL cholesterol, and reductions in abdominal girth.

The authors of the study published in the January 23, 2008 issue of The Journal of the American Medical Association (JAMA), said that to their knowledge, theirs is the first study to document change in glycemic control in obese patients with diabetes following surgically induced weight loss, and added that their findings support early consideration for bariatric techniques in obese patients with type 2 diabetes. The authors concluded that the greater weight loss from bariatric surgery resulted in diabetic remission and metabolic improvements, but suggested the need for a larger, longer-term study.

Many prior significant studies on bariatric mediation of type 2 diabetes include a landmark paper published in 1992 in the journal Annals of Surgery by Walter Pories, professor of surgery and biochemistry at East Carolina University (Greenville, NC, USA), titled "Is type 2 diabetes mellitus (NIDDM) [non-insulin dependent diabetes mellitus] a surgical disease?” The paper reported the remission of diabetes after a gastric bypass procedure.

Another such study titled "Bariatric Surgery, A Systematic Review and Meta-Analysis” was published on October 14, 2004 in The Journal of the American Medical Association (JAMA) by lead author Henry Buchwald, M.D., Ph.D. of the University of Minnesota (Minneapolis, MN, USA). Prof. Buchwald and colleagues reported on the outcome of bariatric surgery on weight loss, operative mortality outcome, and four obesity related comorbidities: diabetes, hyperlipidemia, hypertension, and obstructive sleep apnea. The study concluded that after bariatric surgery, weight loss was achieved in morbidly obese patients, and that a majority of the patients with the obesity related comorbidities experienced improvements or the complete resolution of their condition.


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