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Know when it's time for weight
loss surgery
Consider this option for the morbidly
obese
by Nicolas Christou, MD
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Obesity is defined as a disease in
which excess fat has accumulated to the point where it may adversely
affect health and increase mortality. In the U.S., the prevalence
of obesity is currently 28%, with much higher rates in certain regions
and among specific ethnic groups (National Institutes of Health,
2001). While Canada hasn't quite caught up with its neighbour to
the south, surveillance data of Canadians > 20 years of age shows
a marked rise in obesity (body mass index [BMI] > 30 kg/m2) over
recent years, and there's no evidence that this trend is about to
level off. Indeed, the World Health Organization has recognized
an epidemic of obesity throughout most of the developed and developing
world. Especially alarming is the increasing prevalence of obesity
in children, as it heralds a lifelong disorder with great risk of
related disease.
Morbid obesity is defined as a chronic disease
in which excess adipose tissue results in a BMI > 40 kg/m2, and
is often associated with several comorbidities. In addition, it
impacts on the activities of daily living such as tying shoes, hygiene
- e.g. the ability to wipe oneself after a bowel movement - or fitting
into a car, bus or plane seat. Morbidly obese individuals also suffer
from social stigmatization and discrimination.
Obesity can be treated, however, and research
has shown that the weight loss following bariatric surgery significantly
reduces comorbidities such as diabetes, high blood pressure and
sleep apnea - by up to 70%.
What
are the treatment options for morbid obesity?
There are a variety of medical treatments available, including:
- diet therapy
- physical activity
- behaviour therapy
- pharmacotherapy
The specifics of these treatments aren't
the subject of this article, but it's important to note that medical
management of morbid obesity is unfortunately not often successful.
Fewer than 10% of morbidly obese patients who manage to reduce their
weight using a combination of diet, behaviour therapy and exercise,
can maintain this weight loss for more than 1 year.
Another option for these people is bariatric
surgery, i.e. the treatment of severe obesity through surgery. This
field has continually evolved since its initial sporadic and tentative
introduction in the 1950s. Today, there are a number of different
approaches to choose from that fall into three categories: restrictive,
malabsorptive and a combination of the two. In regard to the question
of when bariatric surgery is indicated, the National Institutes
of Health Consensus Conference in 1991 concluded the following:1
- medical therapies generally fail to control severe obesity - surgery
should be considered for individuals with BMI > 40 kg/m2 - when
comorbidities such as diabetes or sleep apnea are present, consider
surgery starting at BMI > 35 kg/m2. While patients can lose up
to 25 kg over 12 months with medical therapy, almost all will regain
this weight - and more - in the subsequent 5 years. Some repeat
this cycle several times, at which point they get so frustrated
and incapacitated by their weight that they seek surgical therapy.
See Table 1 for a comparison of risks and long-term outcomes of
the most common bariatric surgical procedures.
Does
bariatric surgery produce sustained weight loss?
Several key studies have demonstrated long-term weight loss with
bariatric surgery. The Swedish Obese Subjects (SOS) study, comparing
2,000 obese people treated with either bariatric surgery or conventional
medical means, reported sustained weight changes of 14-25% after
10 years.2 Scopinaro and colleagues found average excess weight
loss to be 74% at 10 years after biliopancreatic diversion (BPD).3
Fobi et al, using the transected banded gastric bypass technique,
reported 68% excess weight loss after more than 10 years.4 Our own
data, comprised of patients who've been followed up for > 10
years, show excess weight loss > 67%, similar to the 67% Biron
and colleagues found for biliopancreatic diversion with duodenal
switch (BPD/DS).5
Is
comorbidity improved?
The sustained weight loss produced by bariatric surgery does indeed
serve to improve or cure the comorbidity associated with obesity.
In 2004, Buchwald et al conducted a meta-analysis of 22,094 morbidly
obese individuals who had weight loss surgery.6 They compared 3
different kinds of procedures: restrictive (adjustable band and
gastroplasty), malabsorptive (BPD/DS), and a combination thereof
(Roux-en-Y gastric bypass). Excess weight loss varied between 48%
and 70%. Diabetes resolved completely in 77% of patients, hyperlipidemia
improved in 70%, and high blood pressure was cured in 62%. Obstructive
sleep apnea got better in more than 80% of study subjects. Our own
data also show reductions in physician and hospital visits for common
diseases such as cancer, infections, musculoskeletal disorders and
cardiovascular disease after people lost weight through bariatric
surgery.
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