Digestive Diseases News
Fall 2009
Study Finds Low Short-term Risks after Bariatric
Surgery for Extreme Obesity
Rates of short-term complications, including
death, were low after bariatric surgery
among participants in the Longitudinal
Assessment of Bariatric Surgery (LABS-1), a study
funded by the National Institute of Diabetes and
Digestive and Kidney Diseases (NIDDK).
Investigators followed 4,776 patients who had
bariatric surgery, evaluating complications and
death rates within the first 30 days after surgery.
“There is a real need to determine safe and effective
treatments for patients with extreme obesity
and its associated medical conditions,” said Susan
Z. Yanovski, M.D., co-director of the NIDDK
Office of Obesity Research and a co-author of
the July 30 The New England Journal of Medicine
report about the study. “This study’s results
can help patients and physicians make informed
decisions about potential risks and benefits of
bariatric surgery.”
Patients were at least 18 years old and had an
average body mass index (BMI) of 44, considered
extremely obese. BMI measures weight in relation
to height. As with most populations undergoing
bariatric surgery, the majority of LABS-1
patients were Caucasian and female. The study
took place over 2 years at 10 medical sites, with
one additional center coordinating data collection
and analyses.
Research centers participating in the National
Institute of Diabetes and Digestive and
Kidney Diseases-funded Longitudinal
Assessment of Bariatric Surgery study include
- Columbia University Medical Center, New York
- Cornell University Medical Center, New York
- East Carolina Medical Center, Greenville, NC
- Legacy Good Samaritan Hospital, Portland, OR
- Neuropsychiatric Research Institute, Fargo, ND
- Oregon Health & Science University, Portland
- Sacramento Bariatric Medical Associates, Sacramento, CA
- University of Pittsburgh Graduate School of Public Health (Data Coordinating Center)
- University of Pittsburgh Medical Center
- University of Washington, Seattle
- Virginia Mason Medical Center, Seattle
Obesity Surgery
Bariatric surgery helps people with extreme
obesity lose weight by limiting food intake,
nutrient absorption, or both. Currently, more
than one-third of U.S. adults have a BMI greater
than 30, considered obese, and an increasing
number surpass a BMI of 40, considered
extremely obese. People who are extremely obese
are potential candidates for bariatric surgery.
People with BMIs less than 40 are also considered
for surgery if they have medical complications
related to obesity.
Participants in LABS-1 underwent adjustable
gastric banding or Roux-en-Y gastric bypass, which was performed through either minimally
invasive laparoscopic surgery or open surgery.
Gastric banding creates a pouch around the top
of the stomach to limit food intake at any one
time. Roux-en-Y gastric bypass also creates a
pouch, but it also redirects food around most
of the stomach and part of the small intestine,
limiting the absorption of food.
Bariatric surgery can have dramatic health benefits,
such as improved blood sugar control or even
reversal of type 2 diabetes. But it also carries
serious risks, including death. The LABS-1
study aimed to evaluate the short-term safety
of bariatric surgery to help doctors and patients
understand the risks.
Short-term Risks
LABS-1 found that within 30 days of surgery,
4.1 percent of patients had at least one major
adverse outcome, defined as death, development
of blood clots in the deep veins of the legs or in
the pulmonary artery of the lungs, repeat surgeries,
or failure to be discharged from the hospital
within 30 days of surgery.
Thirty-day mortality was low, ranging from no
deaths in the laparoscopic adjustable gastric
band group, to six (0.2 percent) in the laparoscopic
Roux-en-Y gastric bypass group, to
nine (2.1 percent) in those undergoing open
Roux-en-Y gastric bypass. The overall risk of
complications also varied by procedure.
The investigators pointed out, however, that
people who underwent some procedures, such
as open Roux-en-Y gastric bypass, tended to be
heavier and sicker than those who underwent
laparoscopic adjustable gastric banding.
After adjusting for patient and center characteristics,
the investigators found no significant
differences in complication risk that could
be attributed to the type of procedure. Some
patient factors, however, increased the risk of
complications, including a preoperative history of
deep vein blood clots and sleep apnea. Patients
with a very high BMI were also at increased
risk—those with a BMI of 75 had a 61 percent
higher risk of complications than those with a
BMI of 53.
Longitudinal Assessment
LABS-1 is part of the LABS consortium, an
NIDDK-funded study launched in 2003 to
examine the short- and long-term benefits and
risks of bariatric surgery for adults with extreme
obesity. LABS-2 will follow a subset of LABS-1
patients to gather longer-term information on
patient characteristics, types of surgeries, medical
and psychosocial outcomes, and economic factors.
The LABS consortium brings together researchers
with expertise in bariatric surgery, obesity
research, internal medicine, endocrinology,
behavioral science, outcomes research, epidemiology,
and other relevant fields to collaboratively
plan and conduct studies that will ultimately lead
to a better understanding of bariatric surgery
and its impact on the health and well being of
patients with extreme obesity.
The NIDDK has publications about weight
control and bariatric surgery. For more information
or to obtain copies, visit the NIDDK’s
Weight-control Information Network at
www.win.niddk.nih.gov.
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NIH Publication No. 10–4552
October 2009
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