the Longitudinal Assessment of Bariatric Surgery
The Longitudinal Assessment of Bariatric Surgery
(LABS) was originally known as the Bariatric Surgery
Clinical Research Consortium. LABS is a National
Institutes of Health (NIH)-funded consortium of
six clinical centers and a data coordinating
center working in cooperation with NIH scientific
staff to plan, develop, and conduct coordinated
clinical, epidemiological, and behavioral
research in bariatric surgery.
What is bariatric
Bariatric surgery restricts stomach size
and/or leads to decreased absorption of
nutrients. These procedures can have significant health benefits, such as reversal of type 2 diabetes or improvements in sleep apnea, but the procedures also carry substantial risks, including death.
people have had bariatric surgery?
According to the former American Society for
Bariatric Surgery (now the American Society for
Metabolic and Bariatric Surgery, or ASMBS), the
number of procedures increased from about 16,000
in the early 1990s to more than 103,000 in 2003.
The ASMBS estimates that 220,000 people in the
United States had bariatric surgery in
the National Institute of Diabetes and Digestive
and Kidney Diseases (NIDDK) establish
- A majority of U.S. adults are overweight or
obese, with more than 30 percent of adults
considered obese (body mass index, or BMI,
greater than 30). An increasing number of
adults are considered extremely obese (BMI
greater than or equal to 40).
- Numerous studies have shown that behavioral
therapy to improve diet and physical activity
can lead to weight loss of approximately 5 to
10 percent over 4 to 6 months.
- When a person loses weight, obesity-related
conditions such as high blood pressure and type
2 diabetes improve, but if a person regains
weight, many of these benefits are lost.
- Because weight loss is so difficult to sustain over the long term, especially in those who are extremely obese, doctors need effective methods for weight loss and weight maintenance in this population.
- Currently, the most effective way for
people with extreme obesity to lose substantial
amounts of weight and improve their weight-related health
conditions is through bariatric
- Although an increasing number of persons
with extreme obesity are undergoing bariatric
surgical procedures, there has been little
systematic research to help determine its risks
and benefits or to provide guidance on
appropriate patient selection. To facilitate
research in this area, NIDDK established
is the goal of LABS?
LABS has brought together experts in bariatric
surgery, obesity research, internal medicine,
endocrinology, behavioral science, outcomes
research, epidemiology, and other relevant fields
to plan and conduct studies that will analyze the
risks and benefits of bariatric surgery and its
impact on the health and well-being of patients
with extreme obesity, and identify the kinds of
patients who are most likely to benefit.
will LABS accomplish its goal?
The consortium has developed a database for
collecting standardized information on patients
undergoing bariatric surgery at the participating
clinical centers. Rigorously collected
information on patient characteristics, types of
surgery, medical and psychosocial outcomes, and
economic factors will ultimately provide
science-based information on the risks and
benefits of bariatric surgery. This
information should lead to rational
recommendations for clinical care.
LABS is also supporting two clinical studies
that were proposed, designed, and approved by the
Steering Committee (see below). These studies
- The impact of surgical procedures on
insulin resistance and type 2 diabetes.
- The impact of bariatric surgery on psychiatric illness and quality of life.
LABS Centers also collect data and specimens
for future research. These data will provide a
valuable resource for the future study of obesity
and its complications.
is LABS organized?
- Through a competitive, peer-reviewed
process, principal investigators at six
clinical centers and a data coordinating center
were funded in September 2003. These
investigators are listed below.
- The principal investigators at the clinical
centers and data coordinating center and the
NIH project scientist comprise the Steering
Committee, which is the governing body for the
- The Steering Committee has met on a
frequent basis to develop the database and plan
the clinical protocols.
- When LABS started, the Steering Committee
members organized working groups to develop the
protocols. The working groups have completed
most of their work, and LABS has established
other subcommittees to address ancillary
studies, adjudication, and publications and
- Investigators, scientists, and clinicians
from the participating centers with relevant
expertise participate in the committees and
is the study timeline for LABS?
LABS was funded in September 2003.
During the first 18 months, investigators
worked together to develop the database, plan
the clinical protocols, and obtain
appropriate human subjects approval. The LABS
database started enrolling patients in March
What has LABS accomplished since
LABS is divided into three parts:
LABS 1, which evaluated the short-term
safety of bariatric surgery for a period of
LABS 2, which evaluates longer-term safety
and efficacy of bariatric surgery
LABS 3, which includes detailed
mechanistic studies in the LABS subjects.
LABS 1 began patient enrollment in March 2005. The study was completed in December 2007 and published in the July 30, 2009 issue of The New England Journal of Medicine. To review study results, visit http://content.nejm.org/cgi/content/short/361/5/445 .
The consortium followed 4,776 adults who underwent bariatric surgery for the first time. Researchers evaluated complications and death rates within the first 30 days after surgery. Listed here are some of the key findings:
- Within 30 days of surgery, 4.1 percent of the patients had at least one major adverse outcome. Adverse outcomes were defined as death, development of blood clots, repeat surgeries, or failure to be discharged from the hospital within 30 days of surgery.
- Mortality rates at 30 days were low: 2.1 percent among the small percentage of participants who underwent open Roux-en-Y gastric bypass, and 0.2 percent among patients who underwent laparoscopic Roux-en-Y gastric bypass. No deaths occurred among patients who underwent laparoscopic adjustable gastric banding.
- Complications varied by procedure, but researchers noted that patients who underwent open Roux-en-Y gastric bypass tended to be heavier and sicker than others in the study. After adjusting data for patient and medical center characteristics, no significant differences in complication risk could be attributed to the type of Roux-en-Y procedure.
- Patient factors can increase risk for complications. For example, patients with a BMI of 75 had a 61-percent higher risk of complications than patients with a BMI of 53. Other factors identified to increase complication risk were a history of deep vein blood clots and a diagnosis of sleep apnea.
LABS 2 has recruited more than 2,400 patients since beginning in February 2006. Enrollment into LABS was completed in April 2009. The patients enrolled in LABS 2 will be followed up at 6 months, 1 year, and then yearly after surgery. Researchers will assess multiple areas before and after surgery to help determine longer-term medical, psychosocial, and economic risks and benefits.
The LABS 3 diabetes study began recruiting patients in December 2007, and it will examine the physiological mechanisms that contribute to improvements of glucose homeostasis in a subset of patients with type 2 diabetes mellitus following gastric bypass surgery.
The LABS 3 psychosocial study began recruiting patients in April 2007 and includes an in-depth assessment of current and prior psychological functioning and eating problems in a subset of LABS 2 subjects who have had bariatric surgery.
funds are available for LABS?
At the start, LABS was funded at $3 million
per year for 5 years, for a total of $15 million.
There were also opportunities for investigators
to apply for additional funding for ancillary
studies first through a request for applications
(RFA) and currently through a Program
Announcement. Information on Program Announcement
PAR-07-024 is at http://grants.nih.gov/grants/guide/pa-files/PAR-07-024.html .
In 2007, NIDDK extended LABS for an additional 5 years to allow researchers to continue to collect data yearly in LABS participants.
The Office of Research on Women’s Health
(ORWH) provided funds to be used for LABS
research related to women’s health issues.
Information on the ORWH can be found at http://www4.od.nih.gov/orwh .
Is recruitment for LABS still ongoing?
No, enrollment in LABS is now complete, although current participants continue to be followed yearly.
I get more information about LABS?
For more information about enrollment in LABS,
see http://www.niddklabs.org .
what other ways might LABS help to advance future
LABS may provide the preliminary data
needed for future investigator-initiated
research on bariatric surgery and obesity.
For example, if LABS investigators are able
to identify metabolic and endocrine changes
that take place after bariatric surgery, this
information would allow researchers to submit
independent applications for full-scale
LABS may encourage researchers to study
the causes and treatments of obesity and its
related health problems by providing access
to laboratory specimens and tissues.
The presence of coordinated obesity
research efforts at participating
institutions may provide opportunities for
research and clinical training to students in
the health professions, as well as to young
Information on the types of data being
collected in the LABS database (not
individual patient information) will be
available on the LABS website, so that other
interested clinicians and researchers can
collect similar data on their patients,
facilitating additional research on bariatric
surgery. See http://www.edc.gsph.pitt.edu/labs/ .
Principal Investigators at the Six Clinical
Paul D. Berk, M.D.
Professor of Medicine
630 West 168th Street
P.O. Box 83 BB912
New York, NY 10029–6574
Anita P. Courcoulas, M.D.
Director, Minimally Invasive Bariatric and
University of Pittsburgh Medical Center
Division of Thoracic and Foregut Surgery
5200 Centre Avenue, Suite 715
Pittsburgh, PA 15232
David R. Flum, M.D., M.P.H., FACS
University of Washington
1950 NE Pacific Street
P.O. Box 356410
Seattle, WA 98195–6410
James E. Mitchell, M.D.
University of North Dakota
Neuropsychiatric Research Institute
120 8th Street South, 2nd Floor
P.O. Box 1415
Fargo, ND 58107
Walter J. Pories, M.D., FACS
Professor of Surgery and Biochemistry
Brody School of Medicine
East Carolina University
600 Moye Boulevard
Greenville, NC 27858
Bruce M. Wolfe, M.D.
Oregon Health and Science University
Division of General Surgery—BTE223
3181 S.W. Sam Jackson Park Road
Portland, OR 97239–3098
Steven H. Belle, Ph.D., MScHyg
Professor of Epidemiology and Biostatistics
Data Coordinating Center
University of Pittsburgh
504 Parran Hall
130 Desoto Street
Pittsburgh, PA 15261
Mary N.B. Horlick, M.D.
Division of Digestive Diseases and Nutrition
2 Democracy Plaza, Room 679
6707 Democracy Boulevard
Bethesda, MD 20892
For additional assistance with media queries,
including a list of LABS investigators with
specific expertise in topics related to bariatric
surgery, contact: Ms. Leslie L. Curtis, M.A.
(301) 496–3585, NIDDK Office of
Communications and Public Liaison, (301)
496–3583, email@example.com. For
more information about LABS, see http://www.niddklabs.org.
For general information about
bariatric surgery, obesity, and related topics,
The Weight-control Information Network
1 WIN Way
Bethesda, MD 20892–3665
Phone: (202) 828–1025; Toll-free:
The National Heart, Lung, and Blood Institute
P.O. Box 30105
Bethesda, MD 20824–0105
American Society for Metabolic and Bariatric Surgery
http://www.asmbs.org (This site is not affiliated with
For information about obesity research
at NIH, see:
NIH Obesity Research
Weight-control Information Network
1 WIN Way
Bethesda, MD 20892–3665
Phone: (202) 828–1025
Fax: (202) 828–1028
The Weight-control Information Network (WIN)
is a national information service of the National Institute of
Diabetes and Digestive and Kidney Diseases
(NIDDK) of the National Institutes of Health,
which is the Federal Government’s lead
agency responsible for biomedical research on
nutrition and obesity. Authorized by Congress
(Public Law 103–43), WIN provides the
general public, health professionals, the media,
and Congress with up-to-date, science-based
health information on weight control, obesity,
physical activity, and related nutritional
Publications produced by WIN are reviewed by
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This publication is not copyrighted. WIN
encourages users of this brochure to duplicate
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NIH Publication No. 04–5573
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Department of Health and Human Services.