Bariatric Surgical and Procedural
in the Treatment of Obese Patients
with Type 2 Diabetes
A position statement from the
International Diabetes Federation Taskforce
on Epidemiology and Prevention
Table of Contents
1. EXECUTIVE SUMMARY . 1
2. BACKGROUND . 3
Why is this position statement needed? . 3
How is obesity defined? . 4
What is the link between obesity and type 2 diabetes? . 6
Negative attitudes toward obesity . 7
Why should bariatric surgery be considered in algorithms for treating obese type 2 diabetes? . 8
Evolving concepts: "Bariatric-Metabolic Surgery" and "Interventional Diabetology" . 10
Is bariatric surgery for severe obesity an effective treatment for type 2 diabetes? . 10
Are there other benefits from bariatric surgery for persons with type 2 diabetes? . 12
Is bariatric surgery cost-effective for the obese person with type 2 diabetes? . 13
What eligibility guidelines already exist on bariatric surgery for type 2 diabetes? . 15
2.10.1 Recommendations for Adolescents . 16
Do bariatric procedures vary in their effectiveness? . 17
What are the risks of bariatric surgery? . 19
What are the components of successful bariatric surgery? . 21
Which patients with type 2 diabetes should be considered for bariatric surgery? . 23
Should bariatric surgery be integrated into diabetes treatment algorithms? .24
Is there equitable access to bariatric surgery? . 25
What is a successful outcome of bariatric surgery for a person with type 2 diabetes? . 25
Novel extra-luminal and endo-luminal procedures and devices and novel bariatric metabolic devices . 26
2.18.1 Novel extra-luminal and endo-luminal procedures and devices . 26
2.18.2 Novel bariatric metabolic devices . 27
3. RECOMMENDATIONS . 29
Management of Diabetes . 29
Research Recommendations . 30
4. IDF CONSENSUS PANEL . 32
5. REFERENCES . 35
1. The classification of weight category by BMI . 6
2. 2 & 10 year diabetes incidence and remission rates from the Swedish Obese Subjects
3. Mortality hazard ratios for white non-smokers . 12
4. Cost effectiveness of bariatric procedures in people with diabetes . 14
5. National and international guidelines for eligibility for bariatric surgery (adults) . 15
6. Estimated weight loss and percentage of those with diabetes who remit at two years
after conventional bariatric procedures (Systematic review (Buchwald et al)) . 17
7. Patient and program factors associated with risk of surgery . 19
8. A summary of more common nutritional concerns for each procedure . 21
9. Eligibility and prioritization for bariatric surgery based on failed non-surgical weight
loss therapy*, BMI, ethnicity** and disease control . 24
Obesity and type 2 diabetes are serious chronic diseases associated with
complex metabolic dysfunctions that increase the risk for morbidity and
The dramatic rise in the prevalence of obesity and diabetes has become a
major global public health issue and demands urgent attention from
governments, health care systems and the medical community.
Continuing population-based efforts are essential to prevent the onset of
obesity and type 2 diabetes. At the same time, effective treatment must also
be available for people who have developed type 2 diabetes
Faced with the escalating global diabetes crisis, health care providers require
as potent an armamentarium of therapeutic interventions as possible.
In addition to behavioural and medical approaches, various types of surgery
on the gastrointestinal tract, originally developed to treat morbid obesity
("bariatric surgery"), constitute powerful options to ameliorate diabetes in
severely obese patients, often normalising blood glucose levels, reducing or
avoiding the need for medications and providing a potentially cost-effective
approach to treating the disease.
Bariatric surgery is an appropriate treatment for people with type 2 diabetes
and obesity not achieving recommended treatment targets with medical
therapies, especially when there are other major co-morbidities.
Surgery should be an accepted option in people who have type 2 diabetes
and a BMI of 35 or more
Surgery should be considered as an alternative treatment option in patients
with a BMI between 30 and 35 when diabetes cannot be adequately controlled
by optimal medical regimen, especially in the presence of other major
cardiovascular disease risk factors.
In Asian, and some other ethnicities of increased risk, BMI action points may
be reduced by 2.5 kg/m2.
Clinically severe obesity is a complex and chronic medical condition. Societal
prejudices about severe obesity, which also exist within the health care
system, should not act as a barrier to the provision of clinically effective and
cost-effective treatment options.
Strategies to prioritise access to surgery may be required to ensure that the
procedures are available to those most likely to benefit.
Available evidence indicates that bariatric surgery for obese patients with type
2 diabetes is cost-effective.
Bariatric surgery for type 2 diabetes must be performed within accepted
international and national guidelines. This requires appropriate assessment
for the procedure and comprehensive and ongoing multidisciplinary care,
patient education, follow-up and clinical audit, as well as safe and effective
surgical procedures. National guidelines for bariatric surgery in people with
type 2 diabetes and a BMI of 35 or more need to be developed and
The morbidity and mortality associated with bariatric surgery is generally low,
and similar to that of well-accepted procedures such as elective gall bladder
or gall stone surgery.
Bariatric surgery in severely obese patients with type 2 diabetes has a range
of health benefits, including a reduction in all-cause mortality.
A national registry of persons who have undergone bariatric surgery should be
established in order to ensure quality patient care and to monitor both short-
and long-term outcomes.
In order to optimise the future use of bariatric surgery as a therapeutic
modality for type 2 diabetes further research is required.
Why is this position statement needed?
The global prevalence of type 2 diabetes is rising dramatically, driven by an
"obesogenic" environment that favours increasing sedentary behaviour and
easier access to attractive calorie-dense foods acting on susceptible
genotype The most recent global predictions by the International Diabetes
Federation (IDF) suggest that there are 285 million people with diabetes
currently worldwide. This is set to escalate to 438 million by 20with a
further half billion at high risk. Diabetes is looming as one of the greatest public
health threats of the 21st century.
Type 2 diabetes is a risk factor for vascular damage: both micro-vascular
(retinopathy; nephropathy and neuropathy) and macro-vascular (premature and
more extensive cardio- , cerebro- and peripheral vascular disease). Premature
mortality and morbidity in diabetes result from such complications. The disease
results from inadequate insulin production and action and results in
hyperglycaemia but is also associated with multiple other dysfunctions involving
lipid metabolism; oxidative stress; inflammation and haemato-rheology. In
addition obesity, by itself, generates similar cardio-metabolic dysfuncti
The dramatic rise in the prevalence of obesity and diabetes has become a
major global public health i The problem is compland will require
strategies at many levels to prevent, control and manage.
There is increasing evidence that the health of obese people with type 2
diabetes, including the metabolic control of diabetes and its associated risk
factors, can benefit substantially from bariatric surgery – that is, surgical
procedures to produce substantial weight l
Several gastrointestinal (GI) operations that were originally designed to treat
morbid obesity also cause dramatic improvement of type 2 diabetes and can
effectively prevent progression from impaired glucose tolerance to diabetes in
severely obese individual In addition, bariatric surgery has been shown to
substantially improve hypertension, dyslipidaemia and sleep apnoand
several reports have documented an improvement of overall survivand
specific reduction in diabetes-related mortalit
Despite a number of evidence-based reviews and consensus statements
having been published regarding the utilisation of bariatric surgery in patients
with obesity and diabthe International Diabetes Federation (IDF) has
not previously considered this rapidly developing area of care for world-wide
use. Therefore a need exists for world-wide expert guidance in the preoperative
evaluation, choice of interventional procedure, perioperative management and
long-term care of patients who seek surgery to improve diabetes control.
The IDF Taskforce on Epidemiology and Prevention convened a Consensus
working group of diabetologists, endocrinologists, surgeons and public health
experts in December 2010 to discuss the appropriate role of bariatric surgery
and other gastrointestinal interventions in the treatment and prevention of
obesity and type 2 diabetes. The specific goals of the panel were:
to develop practical recommendations for clinicians
to identify barriers that currently prevent access to surgery and suggest
interventions for health policy changes that ensure equitable access to
surgery when indicated.
to identify priorities for clinical research
This consensus statement considers primarily established bariatric surgical
procedures. It is acknowledged that this is an emerging field and there is a
large range of novel extraluminal and endoluminal gastrointestinal surgical
procedures and devices that are in the development phase. Some focus
primarily on weight loss and others additional non-weight loss metabolic
benefits. The use of these require further validation before they can be
How is obesity defined?
Obesity is usually classified by body mass index (BMI), calculated as body
weight in kilograms divided by the height in metres squared (kg/m2).
Classifications of BMI, as defined by WHO, based on associations with adverse
health consequences, are listed in Table 1. Other methods, including waist
circumference and central and peripheral fat mass, have also been used but
currently the clearest evidence suggests continued use of BMI as an index of
obesity, particularly when BMI exceeds 30 kg/m2.
BMI categories have been developed primarily in populations of mainly
European ethnicity, and often underestimate health risks in other populations.
In addition, BMI does not necessarily reflect the proportion of body weight that
consists of fat, or the distribution of fat: both these aspects of body composition
can affect the health risks of excess weight. Nevertheless, at present, in the
absence of a better alternative, BMI is the internationally accepted standard
used by researchers and policy makers to allocate individuals to different size
Clinically severe or "morbid" obesity is considered to be Class III obesity or
Class II obesity with significant obesity related co-morbidity including type 2
diabetes (Table 1). Additional cut-points for public health action have been
suggested to address the increased risk of diabetes and cardiovascular disease
in Asian populations and further investigation should examine other at risk
Table 1: The classification of weight category by BMI
Principal cut-off Cut-off points
Obese class III
For Asian populations classifications remain the same as the international
classification but that public health action points for interventions are set at 23,
27.5, 32.5 and 37.
We address eligibility and prioritization for bariatric surgery within the coloured
Source: Adapted from WHO
What is the link between obesity and type 2 diabetes?
Type 2 diabetes is an heterogeneous disorder and, while its causes have yet to
be fully explained, obesity is considered the primary risk facto It has been
estimated that the risk of developing type 2 diabetes is increased 93-fold in
women and 42-fold in men who are severely obese rather than of healthy
weig A small proportion of people with type 2 diabetes, approximately
15% in populations of European origin, are not overweig
In the short term, even modest weight loss in people with type 2 diabetes who
are overweight or obese is associated with improvements in glycaemic control
and associated conditions such as hypertension and dyslipida However,
there is strong evidence that significant weight loss achieved by using lifestyle
and medical methods by obese, particularly severely obese, people is modest
and rarely sustained, particularly in the severely obeThere are now few
medications approved for weight loss with recent withdrawals associated with
Negative attitudes toward obesity
There are widely held community attitudes that the majority of obese individuals
are responsible for their current weight. Severe obesity is too often
misconstrued as a „cosmetic‟ problem and a result of personal failure or lack of
However, this perspective ignores the very strong genetic and developmental
bases to severe obesitcompounded by physical, emotional and societal
issues. It also fails to consider the pervasive obesity promoting effects of
modern societies (the „obesogenic environment‟where an abundant food
supply, changes in food preparation, increasing sedentary behaviour and other
lifestyle factors mitigate against weight control for individuals. Additionally, it
ignores the emerging evidence that body weight is defended by powerful
physiological mechanismmaking long term maintenance of weight loss
In the context of treatment, negative societal attitudes have been a barrier to
the provision of clinically effective, and cost-effective, health care for people
with severe obesity and type 2 diab As noted earlier, obesity is a
consequences for health which requires a comprehensive approach to both
prevention and treatment. People affected by severe obesity often struggle not
only with the health and physical consequences of their chronic condition, but
discrimination at work, socially and within the healthcare system.
Why should bariatric surgery be considered in algorithms for
treating obese type 2 diabetes?
Both insulin resistance and insulin secretory reserve are important in the
pathogenesis of type 2 diabbut to different extents in different people. It
is very important to recognise that not all type 2 diabetes is the same and it is
currently difficult to match the different therapies available to different
phenotypes often resulting to suboptimal responses to therapy.
Type 2 diabetes is a progressive disease and the usual natural history is of
progressive loss of insulin secretory capacity over time and the need for
intensification of therapy and polypharm Arresting this progression is a
formidable therapeutic challenge. Treatment for type 2 diabetes must also
include active management of all cardiovascular risk factors (hypertension,
dyslipidaemia, smoking and inactivity) but glycaemic control is very important –
and not just for prevention of microvascular disease. Years of improved
glycaemic control continue to deliver reduced risk of macrovascular disease
and mortality over subsequent year
Given the role of obesity in the aetiology of type 2 diabetes, guidelines on its
treatment provide that weight loss, with its many benefits, should be the most
logical and cost-effective means of controlling type 2 diab Lifestyle
interventions to promote weight loss and increase physical activity should be
included as an essential component of diabetes treatment regimens.
Medical therapeutic options targeting primarily glucose control are all ideally
added to, and not exchanged for, lifestyle change. Unfortunately, such
strategies have very limited success in controlling blood glucose levels amongst
the severely obese, with many of these patients not achieving targets. A
number of these medications used for treating type 2 diabetes, including insulin,
themselves can result in weight gain.
A major problem for managing type 2 diabetes is the need for continuous
monitoring and intensification of therapies by adding new agents in increasing
doses over time. The ADA and EASD consensus statement recommends that
an HbA1c of 7% is a call to acti Some national guidelines, such as those
from UK‟s NIC support more vigorous intensification of glycaemic therapies
in early stages of diabetes. NICE used HbA1c ≥ 6.5% to increase from
monotherapy but ≥7% for increasing to triple therapies and beyond. This is very
important. In one trial that randomised people with type 2 diabetes and existing
cardiovascular disease to very intensive management targeting HbA1c <6.5%,
mortality was higher in the intensive group, driven by deaths in those people
who failed to show HbA1c improvement as treatment was intensifi This
should not be taken to mean people with early type 2 diabetes should be
treated less vigorously as the legacy effect of early intervention is
A critical issue has been the rate at which health care professionals escalate
therapies. Current approaches that rely on loss of glycaemic control and on
intensifying lifestyle or other time consuming measures set clinicians up for
failure to achieve target
It may be possible to achieve much more in terms of complication prevention –
or even possibly slowed rate of progression – if treatments are started and
intensified early. There have even been suggestions of starting polypharmacy
at diagnosibut there is limited current evidence to demonstrate the efficacy
Apart from the side effect profiles and suboptimal deployment of existing
medical diabetes therapies, there remain issues around patient engagement in
many aspects of their lives. Very few clinical services routinely provide
psychological support to encourage life-long engagement in self-care.
The continuing morbidity and mortality in persons with diabetes is a sign that
the answer as to the best management for type 2 diabetes in terms of
maximising metabolic control is still elusive. Given this scenario, the option of
bariatric intervention needs to be considered in appropriately selected
The term "bariatric" surgery, derived from the Greek word baros for weight,
defines surgical procedures designed to produce substantial weight loss.
Accordingly, goals of bariatric surgery originally evolved around achieving
substantial sustained weight loss. In reality, weight loss is only one of the
outcomes of such surgery. Bariatric surgery can be associated with substantial
hyperglycaemia. hyperlipidaemia, blood pressure, obstructive sleep apnoea
and improved quality of lif
In view of the broad benefits of weight loss and the growing evidence that some
bariatric procedures provide metabolic changes that cannot be explained
completely by their effects on body weight alone, the name "bariatric-
metabolic surgery" is emerging as a more appropriate name.
Is bariatric surgery for severe obesity an effective treatment for
type 2 diabetes?
Bariatric procedures aim to reduce weight and maintain weight loss through
altering energy balance primarily by reducing food intake and modifying the
physiological changes that drive weight regain. There also appear to be
independent metabolic benefits, associated with effects of incretins and
possibly other hormonal or neural changes after some surgical procedure in
addition to weight loss. For example, rapid and sustained improvements in
glycaemic control can be achieved within days of gastric bypass surgery, before
any significant weight loss is evide
A 2009 Cochrane review including patients with and without diabetes concluded
that bariatric surgery resulted in greater weight loss than conventional treatment
in obese class I (BMI>30) as well as severe obesity, accompanied by
improvements in comorbidities such as type 2 diabetes, hypertension and
improvements in health-related quality of lif
A less rigorous systematic review and meta-analysis of 621 studies which
included about 135,000 patients identified 103 studies reporting on the
remission of the clinical and/or laboratory manifestations of diabet Overall,
78.1% of patients had "remission" of diabetes following surgery. Among
patients with diabetes at baseline, 62% remained in remission more than two
years after surgery. There were significant limitations to this review as
remission was largely based on clinical reporting, not HbA1c or other
biochemical outcomes, and follow up of most cohorts poorly described.
The Swedish Obese Subjects study clearly demonstrated the prevention and
sustained remission of type 2 diabetes in a group of 2037severely obese
patients electing to have bariatric surgery when compared with well-matched
controls at 2 and 10 years follow-up (Table 2).
Table 2: 2 & 10 year diabetes incidence and remission rates from the
Swedish Obese Subjects S
Remission based on fasting plasma glucose <7.0 mmol/l and not on hypoglycaemic therap
The extent of remission of type 2 diabetes is influenced by the extent of weight
loss, weight regain, duration of diabetes, the pre-surgery hypoglycaemic
therapy requirements, and the choice of bariatric procedure. In addition each
patient‟s commitment to modifying their diet and levels of exercise within a
framework of ongoing multidisciplinary care will influence outcomes.
Remarkably, there is only a sole acceptably designed prospective randomised
control trial (RCT) which has investigated bariatric surgery specifically as a
treatment for type 2 diab It compared laparoscopic adjustable gastric
banding as part of a comprehensive management program to conventional
diabetes therapy with a focus on weight loss by diet and exercise. After two
years, remission of diabetes was significantly more common in those who had
received surgery (73% vs. 13%).
Are there other benefits from bariatric surgery for persons with
type 2 diabetes?
Severe obesity is associated with a large number of health problems in addition
to type 2 diabetes. A review of more than 1.4 million participants in prospective
studies largely from North America, Europe and Australia show a consistent
progressive rise in the mortality hazard ratios with increasing BM(Figure 3).
A similar analysis by the Prospective Studies Collaboration found the risk of
diabetes-related death was quadrupled for morbidly obese individual
Table 3: Mortality hazard ratios for white non-smok
Follow-up of participants in the Swedish Obese Subjects Study after an
average of 11 years found that bariatric surgery was associated with a 29%
reduction in all-cause mortality after accounting for sex, age and risk factors in
this severely obese grou Bariatric surgery also led to a specific reduction in
cancer incidence in wom Other studies have confirmed this mortality
advantage when compared with community matched control A large
retrospective cohort study of almost 8000 patients who had undergone gastric
bypass surgery were compared for long term mortality with age, sex and BMI
matched controls who had applied for driver‟s licences (Utah, USA The
analysis reported an adjusted long-term all-cause mortality reduction of 40% in
the surgical group. Specific mortality reductions in the operated group were
56% for coronary artery disease, 92% for diabetes, and 60% for cancer when
compared with matched controls.
It would be expected that morbidly obese patients who have bariatric surgery as
a treatment primarily for type 2 diabetes would also experience the benefits of
weight loss on other aspects of their health, for example debilitating
osteoarthritis or obstructive sleep apnoea. Many studies have demonstrated
major improvements in health related quality of life following bariatric surgery
using both generic and obesity specific quality of life instrument
Is bariatric surgery cost-effective for the obese person with type 2
The costs of type 2 diabetes are substantial. In the United States, the lifetime
cost has been estimated at US$172,000 for a person diagnosed at the age of
50, and US$305,000 if diagnosed at the age of The estimate included
both the direct medical costs of diabetes and its complications, and indirect
costs caused by work absence, reduced productivity at work, disability and
premature death. Over 60% of the medical cost was incurred within 10 years of
diagnosis. Bariatric surgery for severe obesity, regardless of diabetes status,
has been assessed as cost-effectivand in some analyses cost saving or
A literature review identified three cost-effective analyses of bariatric surgery for
patients specifically with diabetes (Table 4). All three studies found bariatric
surgery to be either very cost-effective or dominant as a therapy for type 2
diabetes relative to standard therapy. Study analyses have been conservative.
The finding of "cost-effectiveness" indicates that health benefits are achieved at
an acceptable price relative to country-specific cost-effectiveness thresholds.
The "dominant" result indicates that an intervention generates both cost savings
and health benefits over the lifetime of the cohort. This is a rare outcome and
provides the most compelling evidence for funding based on economic criteria.
It is recognized that cost-effectiveness studies have not been conducted in low-
and middle-income countries where high-cost interventions for macro- and
micro-vascular complications may not be available. On the other hand, life
expectancy might indeed be improved by bariatric surgery in these settings and
morbidity decreased. It is up to each health system to determine whether
bariatric surgery with its support services is economically appropriate when
weighed against the provision of essential medicines and other secondary
prevention initiatives, such as foot care, education and retinal screening, which
can be cost-saving in low-income countries.
Cost effectiveness of bariatric procedures in people with
Keating et al
₋ Banding surgery
USA, $US 2005,
₋ Bypass surgery
₋ Banding surgery
₋ Bypass surgery
₋ Banding surgery
Picot et al.UK, €
2006, 20 years
Table notes: *Base case; QALY: Quality-adjusted-life-years.
In mid 2006: 1 Euro = AUD1.72/ GBP0.69/ USD1.28
2.10 What eligibility guidelines already exist on bariatric surgery for type
A number of guidelines exist on the use of bariatric surgery for the treatment of
severe obesity in general, and for the treatment of type 2 diabetes in particular.
They are summarised in Table 5. Most of the existing guidelines reflect the
expert recommendations of the NIH Consensus Development Conference
Statement March 1991. The current NIH website warns that their information is
dated and provided solely for historic purpo
Table 5: National and international guidelines for eligibility for bariatric
Eligible (A):BMI >40
1 weight loss control of
diabetes and weight loss
The guidelines above are qualified by the following common elements
Appropriate non-surgical weight loss measures have been tried and failed
There is the provision for, and a commitment to, long term follow-up
Individual risk to benefit ratio needs to be evaluated
A recent Diabetes Surgery Summit of 50 international experts examined
gastrointestinal (GI) surgery for the management of type 2 diabetes. Delegates
strongly endorsed that conventional GI surgery Roux-en-Y gastric
bypass,(RYGB), laparoscopic adjustable gastric band (LAGB), or bilio-
pancreatic diversion (BPD) should be considered for the treatment of type 2
diabetes in acceptable surgical candidates with BMI >35 kg/m2 who are
inadequately controlled by lifestyle and medical therapy. Further trial evidence
was deemed necessary for inadequately controlled type 2 diabetes in
candidates suitable for surgery with mild-to-moderate obesity (BMI 30–35
2.10.1 Recommendations for Adolescents
Long-term whole-of-family lifestyle change, with high quality medical
management, is the mainstay of paediatric obesity treatment. However,
the growing prevalence of severe obesity in children and adolescents
demonstrates a need for additional therapy. Bariatric surgery is only
considered suitable for adolescents of developmental and physical
maturity. There are a range of guidelines and consensus reports that
have similar recommendations.
A recent position statement was developed by the Australian and New
Zealand Colleges for paediatric physicians and surgeons, and the
Obesity Surgery Society of Australia and New Zealan The statement
recommended surgery be considered if adolescents had BMI >40 kg/m2,
or >35 kg/m2 with severe co-morbidities (including type 2 diabetes),
were aged 15 years or more, with Tanner pubertal stage 4 or 5 and
skeletal maturity, and could provide informed consent. Potential
candidates should have failed a multidisciplinary program of lifestyle +/-
pharmacotherapy for 6 months, and they and their family must be
motivated and understand the need to participate in post-surgical
therapy and follow-up. Surgery should be provided in units affiliated with
teams experienced in the assessment and long-term follow-up of the
metabolic and psychosocial needs of adolescent patients. Very similar
eligibility criteria, with some variation in youngest age and BMI, have
been listed in European and US publicatio
This IDF position statement advises that only 2 procedures, namely
Roux-en-Y gastric bypass (RYGB) and laparoscopic adjustable gastric
banding (LAGB), are currently conventional bariatric surgical procedures
2.11 Do bariatric procedures vary in their effectiveness?
A number of bariatric surgical procedures are effective in achieving weight loss.
Those that involve more extensive surgery, such as RYGB, generally lead to
greater weight loss and more profound metabolic changes, at least initially, than
less invasive, non-diversionary procedures such as LAGB. RYGB procedures
influence the gut hormonal milieu and provide an early non-weight related
improvement in glycaemic control of type 2 diabetes. It is not clear if these
changes are durable or have a fundamental effect on the underlying
mechanisms driving type 2 diabetes. In the longer term weight loss may be the
key benefit. There is absolutely no evidence to support subcutaneous lipectomy
(liposuction) as a treatment for type 2 diabetes in obese patient
A systematic review of the literaturby Buchwald et al. reported that diabetes
remits or improves in the majority of patients after bariatric surgery. The
procedures producing greater excess weight loss lead to higher remission rates
(Table 6). This review, however, was limited by the quality of the available
literature where follow-up varied, there was no consistent definition of
remission, and biochemical measures of remission were usually not reported.
Table 6: Estimated weight loss and percentage of those with diabetes
who remit at 2 years after conventional bariatric procedures
(Systematic review (Buchwald et al))
% Excess BMI loss*
% Remission of Diabetes
Roux-en-Y gastric bypass
*% Excess BMI loss = mean % on BMI in excess of 25 that is lost
The choice of bariatric procedure is complex requiring a careful risk-benefit
analysis and acceptance of variation in regional practice and expertise. The
decision must be made by severely obese patients in consultation with their
bariatric surgical multidisciplinary team. Factors to consider in patients with type
2 diabetes include:
Expertise and experience in the bariatric surgical procedures
The patient‟s preference when the range of risks and benefits, the
importance of compliance, and the effects on eating choices and
behaviours have been fully described.
The patient‟s general health and risk factors associated with high peri-
operative morbidity and mortality.
The simplicity and reversibility of a procedure.
The duration of type 2 diabetes and the degree of apparent residual
The follow-up regimen for the procedure and the commitment of the
patient to adhere to it.
It is important to recognise that all conventional surgical procedures vary in their
risks and benefits, and to date there are few hard data that can be used to
match patients to procedures.
Recommendations made by this consensus apply to currently accepted
bariatric surgical procedures and do not apply to new experimental procedures
The consensus group believe that RYGB, LAGB, BPD and duodenal switch
variant (BPD-SD), and sleeve gastrectomy (SG) as currently accepted
procedurHowever, it was acknowledged that there was limited medium or
long term data regarding SG, and there are safety, nutritional and metabolic
concerns with BPD and BPD (DS). Two procedures were considered accepted
procedures in adolescents - RYGB and LAGB (see the section on Adolescents
2.12 What are the risks of bariatric surgery?
The 30-day mortality associated with bariatric surgery is estimated at 0.1 –
0.3%, a rate similar to that for laparoscopic cholecystectom and described
as „low Programme and patient factors found to be associated with increased
risk are shown in Table 7. The presence of type 2 diabetes has not been found
to be associated with increased risk for bariatric surgery.
Table 7: Patient and program factors associated with risk of surgery.
Program-Surgical Factors "Higher Risk"
Patients Factors "Higher
Surgeon inexperience or in learning curve for the
Low volume centre or surgeon performing surgery
Morbidity and mortality increase with the complexity of
Open compared with laparoscopic procedures
Obstructive sleep apnoea
High risk of pulmonary
Limited physical mobility
The most common complications of bariatric surgery include anastomotic and
staple line leaks (3.1%), wound infections (2.3%), pulmonary events (2.2%),
and haemorrhage (1.7%). Morbidity rates are lower after laparoscopic
procedures, which constitute a steadily increasing proportion of bariatric
A new study by the US Agency for Healthcare Research and Quality reported a
21% decline in complications after bariatric surgery between 2002 and 2006
This work compared complications among >9,500 patients who underwent
obesity surgery at 652 hospitals in 2001–2002 vs. 2005–2006. Complication
rates fell from 24% to 15%, despite increases in the percentage of older and
sicker operative patients. Post-surgical infection rates dropped by 58%, while
other complications such as abdominal hernias, staple leakage, respiratory
failure, and pneumonia diminished by 29–50%. Other complications remained
unchanged (ulcers, dumping, haemorrhage, wound re-opening, deep-venous
thrombosis and pulmonary embolism, heart attacks, and strokes), and none
Early post-operative morbidity and mortality are related to the complexity of the
surgery. The US Bariatric Outcomes Longitudinal Database (BOLD) reviewed
over 57,000 consecutive procedures and reported one or more complication at
1-year rates of 4.6%, 10.8%, 14.9% and 25.7% following LAGB, sleeve
gastrectomy, RYGB and BPD respectivel Thirty day post-surgical mortality
follows a similar trend with 0.1% for LAGB, 0.5% for RYGB and 1.1 for BP
The US Agency for Healthcare Research and Quality reported a 9-fold increase
in bariatric surgery for the period 1998-2004 with a reduction in overall early
mortality from 0.89% to 0.19%. Improvements have been attributed to higher
hospital volumes, a move to laparoscopic surgery and an increase in banding
Longer term surgical complications and need for surgical revisions are not
uncommon, and expected problems are usually specific to the surgical
Early detection and appropriate management of complications is very
important. All those managing post-bariatric surgical patients should have a low
threshold for surgical referral should a complication be suspected. Longer-term
concerns, especially with RYGB and BPD, include vitamin and mineral
deficiencies, osteoporosis and, rarely, Wernicke‟s encephalopathy and severe
hypoglycaemia from insulin hypersecreti Clinical guidelines developed
by the American Association of Clinical Endocrinologists, The Obesity Society,
and American Society for Metabolic & Bariatric Surgery address these
important issue A summary of nutritional risk with each procedure is shown
in Table 8. This does not reflect all nutritional risks and a review of studies for
the diversional procedures RYGB and BPD+/-DS. Long-term dietary advice,
evaluation and supplementation is required for all procedures.
Table 8: A summary of more common nutritional concerns for each procedure
Fat Soluble Vitamins
and Essential Fatty
Recommended daily intake (allowance) or standard multivitamin preparation likely to
Significant risk of deficiency or increased requirements. Specific supplementation is
appropriate especially in higher risk groups.
High risk of deficiency. Additional specific supplementation is necessary to prevent
deficiency. Careful monitoring is recommended. Supplementation well in excess of
daily requirements may be necessary.
Abbreviations also given in legend
The risks of each procedure need to be considered in the light of potential
reductions in mortality, morbidity or comorbidity, quality of life and productivity.
Realistic expectations are important and risk-benefit ratio assessed individually
for each patient, accounting for both peri-operative risk and possible long-term
Continuing efforts are required to monitor the safety, efficacy and long term
effects of bariatric surgery. There is a range of national bariatric surgery
registries and continuing long-term longitudinal studies. We encourage the
expansion of national registries and acknowledge that these must be well
resourced to function appropriately. Severe obesity and type 2 diabetes are
chronic conditions needing a chronic disease approach to care.
2.13 What are the components of successful bariatric surgery?
There is a range of comprehensive guidelines for the use of bariatric
procedures for obesity including the UK National Institute for Health and Clinical
Excellence (2006 the combined American Association of Clinical
Endocrinologists, The Obesity Society, and American Society for Metabolic &
Bariatric Surgery guidelines (2008)and European clinical guidelines (200
Considerations with respect to type 2 diabetes and components of successful
It is important to acknowledge that bariatric surgery is a component of the
ongoing process of chronic disease management of type 2 diabetes and
Bariatric surgery should be performed in high volume centres with multi-
disciplinary teams that understand and are experienced in the
management of obesity and diabetes. Members of the team should have
understanding across disciplines, and work together with common
expectations and goals. The team needs to integrate with primary care,
diabetes management, nutritional and lifestyle support, and surgeon‟s
teams with consistent messages and agreed policies.
The surgical team must have undertaken relevant supervised training, and
have specialist experience in types of bariatric surgery performed within the
Pre-surgical assessment needs to be comprehensive involving MDTs and
include assessment of metabolic, physical, psychological and nutritional
health. Patients should have realistic expectations of the risks and benefits
of surgery along with their lifelong role in lifestyle intervention, nutritional
support and follow-up.
Management of diabetes and other comorbidities should be optimised and
short-term pre-operative weight loss considered to improve health and
visibility at the time of surgery.
The multidisciplinary team need to understand and recognise early and
long term complications in a timely manner, and know when to refer back
to the surgeon, or others for specific care.
Life-long follow-up on at least an annual basis is needed for ongoing
lifestyle support, and post-surgical and diabetes monitoring.
Teams should collect prospective data and measure diabetes outcomes in
methods consistent with IDF recommendations.
Regular, postoperative nutritional monitoring is required, with attention to
appropriate diet after the procedure, monitoring of micronutrient status, and
individualised nutritional supplementation, support and guidance to achieve
long-term weight loss and weight maintenance.
Follow-up should include a psychological evaluation, support and therapy if
appropriate. Mental illness, especially depression, is common in diabetes
and severe obesity.
In order to help sustain ongoing weight loss from bariatric surgery, patients
must be committed to increased levels of ongoing daily physical activity.
All practices are encouraged to engage and promote national programmes
of "centres of excellence" of equivalent and collect prospective data
2.14 Which patients with type 2 diabetes should be considered for
There is clear evidence that bariatric surgery is a very effective therapy for
obese patients with type 2 diabetes. The place of surgery in diabetes treatment
algorithms needs to be established (see below). Currently surgery is considered
optional and as such in the countries with the highest bariatric surgery uptake
less than 2% of eligible patients are treated annually.
Indications for bariatric surgery typically classify those who are eligible for
surgery, but a recommendation of surgical referral as best practice or
prioritisation has not been widely considered. Diabetes management algorithms
should now include points at which bariatric surgery should be considered and
points at which referral is recommended or prioritised (Table 9).
In patients with type 2 diabetes eligibility or prioritisation for surgery should
consider BMI, ethnicity, associated weight related comorbidity, weight trajectory
and the response of diabetes and comorbidity to optimal medical therapy.
Conditional eligibility or prioritisation should be assessed by a team specialising
in diabetes. Surgical referral implies a thorough bariatric surgical MDT
assessment of risk and benefit.
Table 9: Eligibility and prioritisation for bariatric surgery based on failed non-
surgical weight loss therapy*, BMI, ethnicity** and disease control
Eligible for surgery
Prioritised for Surgery
In all cases patients should have failed to lose weight and sustain significant weight
loss through non-surgical weight management programmes, and have type -2 diabetes
that has not responded adequately to lifestyle measures (+/- metformin) with a HbA1c
Action points should be lowered by 2.5 BMI point levels for Asian
*** HbA1c > 7.5 despite fully optimised conventional therapy, especially if weight is
increasing, or other weight responsive co-morbidities not achieving targets on
conventional therapies. For example blood pressure, dyslipidaemia and obstructive
Contraindications for bariatric surgery include; current drug or alcohol abuse,
uncontrolled psychiatric illness, and lack of comprehension of the risks -
benefits, expected outcomes, alternatives and lifestyle changes required with
bariatric surg In addition there are general conditions that would
contraindicate elective surgery, and specific conditions that substantially
increase the risk of surgery, later complications or poor outcomes. These
should be assessed by the surgical team.
2.15 Should bariatric surgery be integrated into diabetes treatment
Existing international treatment guidelines for type 2 diabetes provide little
information or direction on the role of bariatric interventions in treatment. By
contrast, the American Diabetes Association recommends that bariatric surgery
be considered as a treatment option for type 2 diabetes when the patient‟s BMI
exceeds Algorithms developed for treating type 2 diabetes should include
recommendations as to where bariatric surgery is an option and the
circumstances where it should be prioritised.
Almost all severely obese patients are unsuccessful in their efforts to achieve
sustained and significant weight loss and there is evidence that weight loss
induced by bariatric surgery can lead to remission of hyperglycaemia in the
majority of patients with diab Earlier intervention increases the likelihood
of remissi In the remaining patients, residual hyperglycaemia is easier to
manage following bariatric surgery. It can, therefore, be argued that bariatric
surgery for the severely obese with type 2 diabetes should be considered early
as an option for eligible patients, rather than being held back as a last resort.
2.16 Is there equitable access to bariatric surgery?
Obesity is more common in socioeconomically disadvantaged people in the
developed world but the vast majority of bariatric surgery procedures in the
developed world are performed in the private sector. Current access to surgical
treatment for people with severe obesity and type 2 diabetes is not equitable
and discriminates against individuals who are most likely to benefit. There are
particular problems in those emerging countries where rates of severe obesity
are increasing rapidly and health care resources are extremely limited.
There will be resource implications in the short-term from increasing access to
bariatric surgery, but it is essential to consider not just the financial costs of the
procedures and necessary follow-up, but also the potential savings from
achieving improved control of type-2 diabetes, its related metabolic and other
complications and comorbidities.
2.17 What is a successful outcome of bariatric surgery for a person with
type 2 diabetes?
There needs to be an agreed definition of success and on the basis of present
data, the achievable goal of bariatric surgery is not cure, but remission, of the
diabetes state. Improved patient health would be recognised by individualised
optimisation of metabolic state which involves normalisation of metabolic state,
total cholesterol < 4 mmol/l; LDL cholesterol < 2 mmol/l
triglycerides < 2.2 mmol/l
BP < 135/85 mmHg
>15% weight loss
With reduced medication from the pre-operated state or without other
medications (where medications are continued, reduced doses from pre-
surgery with minimal side effects would be expected)
A substantial improvement in metabolic state may be defined as:
Lowering of HbA1c by > 20%
LDL < 2.3 mmol/l
BP < 135/85 mmHg
With reduced medication from the pre-operated state
The above definitions, with a focus on diabetes, complement broader success
measures including substantial sustained weight loss, improved quality of life
and improvement or remission of obesity associated comorbidity.
2.18 Novel extra-luminal and endo-luminal procedures and devices and
novel bariatric metabolic devices
2.18.1 Novel extra-luminal and endo-luminal procedures and devices
Several novel procedures have developed from elegant experiments
using rodent models used to examine the mechanism of action of
bariatric surgery. The aim has been to enhance the non-weight loss
glycaemic control benefits of the GI interventions. These procedures
may evolve as therapy for type 2 diabetes in those without a significant
weight issues. These novel procedures include duodenal-jejunal
bypa(DJB) and ileal interpositi(IT).
First described by Rubino, DJB is a stomach-sparing bypass of a short
portion of proximal intestine, comparable to the segment excluded in a
standard RYGB. A number of early human clinical trials have been
performed and improvements in glycaemic control have been reported,
but these may be less impressive in subjects with a lower BM
Ileal interposition (IT) involves the surgical transposition of a small
segment of ileum into the proximal intestine. Generally, short term
studies in humans have reported improved glycaemi
These procedures remain experimental and are likely to require
technical refinements before larger scale longer-term safety and efficacy
2.18.2 Novel bariatric metabolic devices
Multiple, mostly novel, devices and techniques are being explored to
utilise the GI tract‟s putative mechanism for altering energy balance and
for non-weight loss effects on glucose tolerance. In general the
techniques can be divided by mode of placement into those that are
upper GI endoscopic or laparoscopic, with some combining approaches.
Endoscopically placed upper GI devices include the simple positioning
of a device in the upper GI tract. Examples include intra-gastric balloons
which are currently available for temporary placement (usually 6
months, but repeat treatment for extending the duration of treatment
beyond 2 years have been reported) and which provide 10-15% weight
loss during the period of placement, plus a range of novel devices under
development which are placed in the stomach to mimic restriction, or
placed in the trans-pyloric area to delay or regulate gastric emptying.
Some endoscopically placed devices are physically fixed to the upper GI
tract to mimic proximal gastric restriction of the LAGB, while some use
endoluminal impervious sleeves to bypass the gastro-duodenal upper
jejunal area to mimic the RYGB, or bypass the duodenum and proximal
jejunum to mimic the DJB.
A range of laparoscopic procedures to place novel electronic gastric or
gastro-duodenal motility stimulators, and vagal nerve blocking devices
are also under investigation. Results in humans to date have been
mixed with some devices providing inadequate weight loss and others
promising results. These are considered less invasive than most
conventional bariatric surgical procedures.
Whilst there is excitement in the novel medical device area the efficacy,
safety, durability and clinical utility of many of these procedures in the
management of obese people with type 2 diabetes is still to be
Management of Diabetes
3.1.1 Bariatric surgery is an appropriate treatment for people with type 2
diabetes and obesity (BMI equal to or greater than 35) not achieving
recommended treatment targets with medical therapies, especially
where there are other obesity related co-morbidities. Under some
circumstances people with a BMI 30-35 should be eligible for surgery
3.1.2 It is up to each health system to determine whether bariatric surgery
with its support services is economically appropriate.
3.1.3 Surgery should be considered as complementary to medical therapies to
reduce micro-vascular and cardiovascular risk
3.1.4 Patients should be assessed and managed by experienced multi-
3.1.5 Glycaemic control should be optimised peri-operatively and should be
closely monitored after surgery
3.1.6 On-going and long-term nutritional supplementation and support must
be provided to patients after surgery
3.1.7 Apart from conventional procedures now in use new techniques and
devices should be explored in research settings only. Conventional
procedures should be standardised. Other techniques, variations and
novel devices can be introduced when supported by an evidence base.
3.1.8 Procedure selection requires appropriate assessment of risk vs. benefit
of each operation as part of the process for selecting the surgical
treatment options for an individual patient.
3.1.9 New bariatric procedures require robust assessment for their efficacy,
safety, and durability using similar principles to those for assessing new
drug therapies and having regards to the benefits and risks of
3.1.10 Regional surgical expertise, multidisciplinary team experience, and
documented quality outcomes are important factors in the regional
choice of bariatric procedures.
3.1.11 There should be a minimal accepted data set for pre-surgery and follow-
up to allow audit of clinical programmes eg.
Fasting glucose and insulin
Retinopathy status (recent eye exam)
Nephropathy (eg test for microalbuminuria within previous year)
Liver functions tests
Blood pressure measurement
Foot exam (recent)
Documentation of medications – (glycaemia, lipids & HT)
These should be used preoperatively.
Fasting C peptide where available
Auto- antibody status eg anti-GAD where available
3.1.12 All longitudinal studies should include quality of life as one of the
3.1.13 It should be recognised that a prolonged period of normalisation of
glycaemic control has benefit even if there is eventual relapse.
3.2.1 Studies are needed to establish more robust criteria than BMI for
predicting benefit from surgery and define which patients benefit most
from which procedures.
3.2.2 Studies are needed to establish the benefit of surgery for persons with
diabetes and BMI < 35.
3.2.3 Studies are needed to establish whether bariatric procedures prevent or
slow the progressive loss of beta-cell function characteristic of type 2
3.2.4 Studies are required to document the course of complications after
surgery obtain evidence that surgery stabilises and ideally improves
3.2.5 Studies are needed to establish the duration of the benefit of surgery.
3.2.6 Studies are needed to establish the mechanisms of the success of
surgery and the mechanisms associated with recurrence.
3.2.7 Studies are needed to establish the long term complications of surgery.
3.2.8 New techniques should be assessed rigorously for efficacy and safety
and ideally mechanisms, and demonstrate their equivalence or
superiority to classical surgical techniques, moving to human studies
after appropriate pre-clinical studies.
3.2.9 Studies are needed to define the best regimens of diabetes
management post bariatric surgery.
3.2.10 It will be important to phenotype candidates for surgery to define what
will be the most appropriate bariatric procedure for persons with
diabetes in different age groups, different duration of diabetes etc.
3.2.11 Randomised controlled trials are needed to evaluate and compare
different bariatric procedures for the treatment of diabetes between
themselves as well as emerging non-surgical therapies.
IDF Consensus Panel
Professor George Alberti*
Imperial College, London and Newcastle University, UK
Professor John B. Dixon*
Baker IDI Heart & Diabetes Institute, Melbourne, Australia
Professor Francesco Rubino*
Weill Cornell Medical College, USA
Professor Paul Zimmet*
Baker IDI Heart & Diabetes Institute, Melbourne, Australia
Professor Stephanie Amiel
King's College, London, UK
Professor Louise A. Baur
University of Sydney, Australia
Professor Nam H. Cho
Deparment of Preventive Medicine, Ajou University School of Medicine, Korea.
Dr. Bruno Geloneze
University of Campinas (UNICAMP), Brazil
Professor Jan Willem Greve
Atrium Medical Center, Parkstad Heerlen, Netherlands
Professor Linong Ji
Peking Unviersity People's Hospital, China
Dr. Muffazal Lakdawala
Saifee Hospital, Mumbai, India
Professor Wei-Jei Lee
Ming-Sheng General Hospital, National Taiwan University, Taipei, Taiwan
Professor Pierre Lefebvre
International Diabetes Federation and Department of Medicine, University of
Dr. Carel le Roux
Imperial College London, UK
Professor Jean-Claude Mbanya
International Diabetes Federation, Younde, Cameroon
Professor Gertrude Mingrone
Catholic University of Rome, Italy
Professor Philip R. Schauer
Cleveland Clinic Lerner College of Medicine, USA
Professor Luc Van Gaal
Antwerp University Hospital, Belgium
Dr. David Whiting
International Diabetes Federation, Brussels, Belgium
Professor Bruce M. Wolfe
Oregon Health and Science University (OHSU), USA
We acknowledge the contributions of Catherine Keating for reviewing the cost-
effectiveness of bariatric surgery, and Gary Wittert and Joe Proietto for their
constructive review of this Position Statement. We also acknowledge the assistance
and direction provided by a group of Australian endocrinologists chaired by Professor
The consensus meeting was supported with an unrestricted educational grant by:
Allergan Inc, Irvine, CA, USA
Ethicon, Ethicon Endo-Surgery, Inc, Cincinnati, Ohio, USA
MetaCure Inc, Mount Laurel, NJ, USA
These companies played no role in the discussion or preparation of this position paper.
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TB treatment Multi-arm multi-stage trial to identify regimens to include in a phase III trial for shorter treatment of tuberculosis The PanACEA consortium aims to control. A number of interim analyses are The remaining 4 studies that were initially performed during the study to identify shorten TB treatment and consists of
ORIGINAL INVESTIGATION HEALTH CARE REFORM An Empirical Model to Estimate the Potential Impactof Medication Safety Alerts on Patient Safety, HealthCare Utilization, and Cost in Ambulatory Care Saul N. Weingart, MD, PhD; Brett Simchowitz, BA; Harper Padolsky, MD; Thomas Isaac, MD, MBA, MPH;Andrew C. Seger, PharmD; Michael Massagli, PhD; Roger B. Davis, ScD; Joel S. Weissman, PhD