Laparoscopic adjustable gastric banding in patients with insulin-treated type 2 diabetes

To the Editor: Laparoscopic adjustable gastric banding (LAGB) is the most common bariatric surgery performed in Australia, and diabetic patients represent an important target population.1 In one of few trials in type 2 diabetes, 73% of 30 LAGB-treated obese patients reverted to normal glucose tolerance by 2 years, compared with 13% of 30 obese patients randomly assigned to treatment with changes to their lifestyle.2 These Australian data precipitated publicity implying that many people with type 2 diabetes were cured by LAGB.3,4 However, only recently diagnosed patients were recruited. The benefits of LAGB in those with diabetes of long duration (and usually with a substantial loss of pancreatic beta-cell function5) may not be as dramatic.

We reviewed the records of eight patients with insulin-treated type 2 diabetes (aged 40–65 years, with a diabetes duration of 4–39 years) referred for LAGB by one of us (T D) to two established bariatric surgical units over 4 years. All eight patients had a diabetes-specific review within 2 months of surgery and at 3 and 6 months postoperatively, and six patients had a further review at 12 months. Perioperative diabetes management was coordinated by the anaesthetist and ward staff, but patients were encouraged to contact their doctor or regional diabetes education unit for advice at any time if necessary. Patients attended the bariatric unit for saline insertion into the band once or twice before their diabetes-specific review at 3 months.

No patients developed postoperative complications. The median weight loss was 14% at 6 months and 20% at 12 months (Box). By 3 months, insulin doses had been reduced in all patients and two had stopped using insulin. However, most had increased their insulin doses at 6 months (and the two who had discontinued insulin started using it again) because of unsatisfactory glycaemic control. During the 12 months’ follow-up, only one patient stopped using insulin and remained without its use without an unacceptable glycated haemoglobin (HbA1c) increase.

Although our eight patients achieved the same median percentage weight loss at 1 year as trial patients with diabetes of relatively short duration achieved over 2 years,2 insulin use was still required in most cases. When asked, the patients suggested that inappropriate initial insulin reductions were not because they experienced hypoglycaemia, but rather because they expected substantial LAGB-associated metabolic improvement. Perhaps this was encouraged by media coverage3,4 and/or concerns of bariatric unit staff that continuing their insulin therapy might retard their LAGB-associated weight loss. In some cases, problems with insulin adjustment and glycaemia overshadowed the psychological benefits of progressive weight loss.

These preliminary observations suggest a need for more data on diabetes management after LAGB, to inform acute treatment modification and to provide a realistic idea of the effects of LAGB on longer term disease outcomes.

Changes in body weight, insulin dose and HbA1c after LAGB in eight patients with insulin-treated type 2 diabetes

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HbA1c = glycated haemoglobin.
LAGB = laparoscopic adjustable gastric banding.
Open-circle line = patients who discontinued insulin during the first 3 months of follow-up.