|NIH Study Finds Low Short-term Risks After
Bariatric Surgery for Extreme Obesity
Short-term complications and death rates were low following bariatric
surgery to limit the amount of food that can enter the stomach,
decrease absorption of food or both, according to the Longitudinal
Assessment of Bariatric Surgery (LABS-1). The study was funded
by the National Institute of Diabetes and Digestive and Kidney
Diseases (NIDDK), part of the National Institutes of Health. Results
are reported in the July 30 issue of the New England Journal of
Less than 1 percent (0.3 percent) of patients died within 30
days of surgery, further supporting the short-term safety of bariatric
surgery as a treatment for patients with extreme obesity.
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.
"Evaluating the 30-day safety outcomes of bariatric surgery
in large populations is an essential step forward," according
to co-author Myrlene Staten, M.D. senior advisor for diabetes translation
research at NIDDK, part of NIH. "And LABS-1 data are from
all patients who had their procedure performed by a surgeon participating
in the study, not from just a select few patients."
Various types of bariatric surgery limit food intake, nutrient
absorption or both. The major types of surgery undergone by participants
in this study included laparoscopic adjustable gastric banding,
laparoscopic Roux-en-Y gastric bypass and open Roux-en-Y gastric
bypass. Gastric bands create a pouch around the top of the stomach
to limit food intake at any one time. Gastric bypass also creates
a pouch and redirects food around most of the stomach and part
of the small intestine, limiting the absorption of food.
The LABS-1 consortium followed 4, 776 patients who had bariatric
surgery for the first time, evaluating complications and death
rates within the first 30 days after 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 white and female. The study
took place over two years at 10 medical sites, with one additional
center coordinating data collection and analyses.
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 undergoing
some procedures, such as open Roux-en-Y gastric bypass, tended
to be heavier and sicker than those undergoing laparoscopic adjustable
gastric banding, and after adjusting for patient and center characteristics,
there were no significant differences in complication risk that
could be attributed to the type of procedure. There were some patient
factors that increased the risk of complications, including a preoperative
history of deep vein blood clots and sleep apnea. Patients with
a very high BMI, a measure that relates weight to height, 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.
Currently, more than one third of U.S. adults are obese (BMI higher
than 30) and an increasing number are extremely obese (BMI higher
than 40), according to the U.S. Centers for Disease Control and
Prevention. People who are extremely obese are potential candidates
for bariatric 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., a co-author of the paper and co-director
of NIDDK's Office of Obesity Research. "This study's results
can help patients and physicians make informed decisions about
potential risks and benefits of bariatric surgery."
LABS-1 is part of the Longitudinal Assessment of Bariatric Surgery
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 patients
to gather longer-term information on patient characteristics, types
of surgeries, medical and psychosocial outcomes and economic factors.
The 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 better understanding of bariatric surgery and its impact
on the health and well-being of patients with extreme obesity.
LABS-1 was conducted by researchers at the following centers:
- Columbia University Medical Center, New York City
- Cornell University Medical Center, New York City
- East Carolina Medical Center, Greenville, N.C.
- Neuropsychiatric Research Institute, Fargo, N.D.
- Oregon Health & Science University, Portland
- Legacy Good Samaritan Hospital, Portland, Ore.
- Sacramento Bariatric Medical Associates, Sacramento, Calif.
- University of Pittsburgh Medical Center
- University of Washington, Seattle
- Virginia Mason Medical Center, Seattle
- University of Pittsburgh Graduate School of Public Health (Data
For more information about the LABS-1 study, search for NCT00433810
Information about the larger LABS study is at www.niddkLABS.org.
Learn more about weight control by visiting NIDDK's Weight-control
Information Network at www.win.niddk.nih.gov. "Bariatric
Surgery for Severe Obesity" describes procedures, risks and
potential benefits at http://win.niddk.nih.gov/publications/gastric.htm.
More information about NIH's obesity research is available at www.obesityresearch.nih.gov.
The NIDDK, part of NIH, conducts and supports basic and clinical
research and research training on some of the most common, severe
and disabling conditions affecting Americans. The Institute's research
interests include: diabetes and other endocrine and metabolic diseases;
digestive diseases, nutrition, and obesity; and kidney, urologic
and hematologic diseases. For more information, visit www.niddk.nih.gov.
The National Institutes of Health (NIH) — The Nation's
Medical Research Agency — includes 27 Institutes and Centers
and is a component of the U.S. Department of Health and Human Services.
It is the primary federal agency for conducting and supporting basic,
clinical and translational medical research, and it investigates
the causes, treatments, and cures for both common and rare diseases.
For more information about NIH and its programs, visit www.nih.gov.