Sept. 15, 2008 -- Gastric bypass
surgery may be less successful for patients with
diabetes and patients with a larger stomach pouch size, say researchers
from the University of California, San Francisco.
The researchers examined data from 310 patients who underwent
gastric bypass surgery at the University of California, San Francisco,
Medical Center between 2003 and 2006.
Gastric bypass surgery is a common surgical treatment in North America to
obesity. During the procedure, a surgeon reduces the size of a person's
stomach to create a smaller pouch. This allows a person to feel full sooner.
The pouch is then connected to a lower section of the small intestine,
bypassing part of the small intestine, to limit the calories and nutrients the
body can absorb.
"When performed in high-volume centers and with a low rate of complications,
gastric bypass provides sustained and meaningful
weight loss, significant improvement in quality of life, improvement or
resolution of obesity-associated comorbidities and extended life span," the
Even so, 5% to 15 % of patients do not lose a successful amount of
To understand why, the researchers observed the study's participants for 12
months following their surgery. They examined variables that could affect a
patient's ability to lose a successful amount of weight, including older age,
gender, greater initial weight and BMI, race, marital status, insurance status,
the presence of
type 2 diabetes, and larger pouch size.
Poor weight loss was defined as losing 40% or less of the excess body weight
12 months after the surgery and good weight loss as losing more than 40% of the
Before the surgery, their average
body mass index (BMI) was 52. One year later, it was 33.9 on average.
Thirty-eight of these patients (12.3%) had poor weight loss with a final
average BMI of 43.8. The 87.7% of participants who had successful weight loss
had an average BMI of 32.5.
After taking into account many variables, the researchers found that having
diabetes, or a larger stomach pouch were linked to higher odds for poor weight
loss after gastric bypass surgery. When they looked specifically at patients
with diabetes, they found that poor weight loss was more strongly linked to
those who were taking insulin compared to patients without diabetes.