NEW YORK (Reuters Health) – Obese individuals with diabetes lose less weight with gastric bypass surgery than do their peers without diabetes, researchers at the University of California, San Francisco, report.
With gastric bypass surgery, a small stomach pouch is created, which limits food intake by making the patient feel full sooner after eating than he or she otherwise would. In addition, a portion of bowel is connected to the stomach, effectively bypassing the first portion of the bowel where most food absorption occurs.
The new findings, which appear in the Archives of Surgery, also indicate that a bigger stomach pouch leads to inferior weight loss.
Up to 15 percent of patients who undergo gastric bypass surgery fail to lose enough weight to appreciably improve their health, Dr. Guilherme M. Campos and colleagues note.
The team examined factors related to weight loss 12 months after gastric bypass surgery for 310 patients treated at their center between 2003 and 2006. The average age was 45 years and the average body mass index (BMI), the ratio of body weight to height, was 54. A BMI of 20 to 25 is considered normal, while a BMI over 50 is considered “super obese,” the most severe category of obesity.
Overall, patients had lost 60 percent of their excess weight by 1 year after surgery, resulting in an average BMI of 34.
Thirty-eight patients (12 percent) had poor weight loss, defined as a drop of 40 percent or less of excess weight. For these patients, their BMI at 1 year was 44.
On final analysis, diabetes increased the risk of poor weight loss by threefold. Similarly, a larger pouch size more than doubled the risk.
The authors believe that the poor weight loss seen with diabetes may be due to the use of insulin or related drugs to treat the disease. Insulin is a well known anabolic hormone, meaning that it promotes the development of body tissues.
For surgeons performing this operation, the authors emphasize that they should strive to create a small stomach pouch so their patients can achieve optimal weight loss.
SOURCE: Archives of Surgery, September 2008.