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Because of the bad press about weight-loss drugs in recent years,
physicians and patients alike may be suspicious of all such medications.
However, the agents currently approved for long-term use warrant
a second look. For overweight patients who need to lose weight
to prevent or lessen the risk of obesity-related disease, these
drugs can help achieve medically significant weight loss when
used as an adjunct to lifestyle changes. Here, Drs Wyatt and Hill
dispel some myths about weight-loss medications and suggest ways
to maximize their effectiveness when prescribed in selected patients.
Wyatt HR, Hill JO. What role for weight-loss medication? Weighing
the pros and cons for obese patients.
Weight-loss medications are not widely prescribed, and physicians
have many legitimate reasons to be cautious and skeptical about
recommending these drugs for their obese patients. First, weight-loss
medications in general have had a history of poor outcomes and
"unintended consequences". Past use of the amphetamine-derived
addictive stimulants and the unexpected side effects involving
heart valves from use of "phen-fen" have not helped
to create confidence in the use of weight-loss drugs.
Second, only recently has obesity been recognized as a "legitimate"
metabolic disease with both a physiologic and a genetic basis.
In the past, obesity was thought of as a social condition or a
character flaw stemming from laziness or lack of willpower, not
a justifiable disease process deserving of medical attention,
much less medication. The consensus of the medical profession
was that legitimate doctors did not treat obesity.
Third, weight management is just beginning to make its way into
the medical school curriculum. Consequently, the majority of currently
practicing physicians likely did not receive formal medical training
in obesity. Rather, they have had to acquire their own information
about the rationale for treating obesity and about the therapeutic
options available. Fortunately, this situation is slowly changing,
and weight management is becoming an important part of medical
school and residency training.
Advances in weight management
The severe impact of obesity on overall morbidity and mortality
is indisputable. Primary care physicians can expect that more
than half of their patients will have weight issues that potentially
contribute to suboptimum health. Currently, more than 60% of the
US population is either overweight (ie, body mass index [BMI],
25.0 to 29.9 kg/m2) or obese (ie, BMI, >30 kg/m2).
Most physicians realize the necessity of addressing weight issues
with their patients, and there is rising demand for better tools
and strategies for managing weight. Recent research has greatly
expanded the understanding of obesity as a genetic, physiologic
disease that manifests itself in an environment where physical
activity levels are low and caloric intake potential is high.
Today evidence-based guidelines are available to guide physicians
in obesity management, including the appropriate use of medications.
At present, there are safe and effective weight-loss medications
that, when prescribed appropriately, are not associated with any
of the adverse health-related outcomes of earlier agents. Although
more effective medications presumably will be developed over time,
the current agents can produce sufficient weight loss to significantly
improve health and decrease the risk of many chronic diseases.
The understanding is growing that chronic incurable diseases,
including obesity, require long-term use of medication. For the
first time, many physicians are receiving training about the treatment
of obesity, a disease that affects about one third of the US population
and deserves serious medical attention.
Three myths about weight-loss medications
Why should physicians prescribe weight-loss medications for treatment
of obesity? Perhaps a better way to address this question is to
consider the converse: Why shouldn't physicians prescribe medications
when necessary to treat obesity?
MYTH 1. Obesity is a lifestyle problem; therefore, medications
are not necessary.
The data suggest that this is not the case and that lifestyle
changes alone do not solve the problem for all patients. As mentioned,
obesity has a definite physiologic and genetic basis that is expressed
as excessive weight in an environment of low energy expenditure
and high energy intake. Research has clearly shown that individual
differences in physiology impact body weight and may affect how
much weight is gained or lost under specific lifestyle conditions.
It may be more difficult for some individuals to lose weight and
maintain the loss than for others.
Medications are routinely used to treat metabolic diseases such
as diabetes, hypertension, and hyperlipidemia. As with obesity,
individual physiologic differences affect the risk of diabetes
as well as treatment of the disease. Despite this similarity,
many physicians who routinely prescribe diabetes medications do
not think obesity needs medication treatment. The old perception
that obesity is not a real medical issue or somehow does not deserve
medication may remain in the back of the mind of many physicians.
Long-term changes in dietary and physical activity patterns likely
could completely treat obesity in many patients. Interestingly,
such changes also could effectively treat type 2 diabetes, hypertension,
and hyperlipidemia in many patients. However, the reality is that
long-term lifestyle changes are difficult for most people, and
medications are given as an adjunct to lifestyle interventions.
This is a familiar concept to physicians who accept this model
for most chronic disease states.
For example, although diet and exercise alone could effectively
control type 2 diabetes in many patients, physicians rarely insist
that lifestyle change be the only treatment used for long-term
control of blood glucose levels. They know that long-term lifestyle
changes, while possible for some patients, do not occur in the
majority of patients; therefore, diabetes medication is routinely
prescribed as an adjunctive treatment. Do some diabetic patients
live a lifestyle that makes their diabetes much harder to treat?
This is absolutely true, but lifestyle change is rarely the only
intervention that is offered to those patients. Thus, the role
and rationale for use of medications to treat obesity are very
similar to those in other chronic diseases requiring adjunctive
drug therapy when diet and physical activity have not been successful.
MYTH 2. Taking weight-loss medications is too risky.
All medications involve some degree of risk, and weight-loss medications
are no exception. As with any other disease that can be treated
with medication, physicians must decide which obese patients to
treat. Generally, the health risks of obesity increase as the
BMI increases. This relationship between health risks and BMI
is the reason why the evidence-based guidelines for obesity treatment
established by the National Heart, Lung, and Blood Institute (NHLBI)
recommend that weight-loss medications be considered in patients
with a BMI of 30 kg/m2 or higher and in those with a BMI of 27
kg/m2 or higher who have an obesity-related comorbid illness.
Although weight-loss medications carry some measurable degree
of risk, a BMI of 30 kg/m2 or higher also carries a significant
health risk, and it is generally thought that successful weight
reduction will produce a benefit that is worth the medication
risk. Persons with obesity-related comorbidities (eg, hypertension,
diabetes, dyslipidemia, sleep apnea, heart disease) are at even
higher risk from excessive weight. Therefore, the NHLBI as well
as the US Food and Drug Administration (FDA) have changed the
guidelines for potential use of weight-loss medication to include
patients with a BMI as low as 27 kg/m2 . Similarly, surgery for
obesity may be considered in patients with a BMI of 40 kg/m2 or
higher. Because the risk associated with surgery is greater than
the risk with medication, a higher BMI cutoff was specified in
the guidelines to balance the risk ratio. In contrast, in patients
with a BMI lower than 25 kg/m2, the risk of the medication outweighs
any benefit because such patients are not at great risk medically
from their current weight.
The risk of a treatment method becomes acceptable when the risk
of not treating a condition outweighs the risk of the treatment.
The risk-benefit ratio model is not unique to obesity but, rather,
is commonly a part of decision making in medicine. One role of
obesity medication is to decrease the risk of development of health-related
complications due to obesity or to make treatment of existing
comorbidities easier and more effective.
MYTH 3. Weight-loss medications do not produce enough weight
loss to make them a useful treatment option.
Successful short-term weight loss is fairly common and can be
achieved with a number of interventions. However, the ultimate
goal in obesity management is long-term weight loss. Maintaining
weight loss for longer than 1 year is difficult to achieve routinely,
probably because of both physiologic and behavioral adaptations
to the intervention. There is some evidence to suggest that physiologic
processes which make regaining weight more likely may come into
play after a short-term weight reduction. Such processes include
a drop in metabolic rate, an increase in appetite, and a strengthening
in preference for high-energy foods. These types of physiologic
processes would discourage energy balance after weight reduction
and increase the likelihood of a positive energy balance. Thus,
physiologically, the body may "fight against" the weight
reduction.
In addition, some evidence suggests that continuing the behavioral
interventions responsible for short-term weight reduction may
be difficult for many people over time in the current environment.
For example, a person may lose weight by eating a very-low-calorie
diet (ie, 1,000 kcal) and exercising 2 hours a day. This diet
and exercise pattern is very different from his or her eating
and activity levels before the weight loss. Most people find it
extremely difficult to maintain such behaviors over long periods
and ultimately return to their previous eating and activity levels
and, thus, previous body weight. A major contributing factor to
this difficulty is the current environment, in which people are
constantly being prompted to eat more and move less in response
to large serving sizes of great-tasting, inexpensive food as well
as advances in technology that encourage sedentary lifestyles.
Weight-loss medications are a tool to help combat these physiologic
and behavioral pressures over the long term. Use of sibutramine
hydrochloride (Meridia) and orlistat (Xenical), the two weight-loss
drugs that are approved by the FDA for long-term use, can make
it easier for patients to adhere to lifestyle changes for longer
periods. For example, sibutramine decreases appetite, which makes
eating fewer calories easier over time. Orlistat blocks one third
of the dietary fat consumed, thereby easing some of the pressure
on patients to watch how much fat they eat. These medications
can help some patients be more successful in losing weight and
maintaining the loss.
This effect can be seen in the categorical data from long-term
clinical trials of sibutramine and orlistat. Most physicians mistakenly
focus only on the average amount of weight loss a medication can
produce in a short-term clinical trial. However, the critical
result is how many patients can reach the medical goal of 5% to
10% weight loss and maintain it over the long term. At 2 years
in the Sibutramine Trial of Obesity Reduction and Maintenance,
69% of patients receiving sibutramine treatment were maintaining
a significant weight reduction of 5% or higher and 46% were maintaining
a 10% or higher reduction, compared with 44% and 21%, respectively,
of patients receiving placebo. The role of weight-loss medications
is to maximize the number of patients who are succeeding at maintaining
a medically significant weight reduction on a long-term basis.
These data allow physicians to estimate how many of their patients
potentially could reach a significant long-term weight reduction
using the medication as an adjunct to lifestyle change.
Key concepts in prescribing a weight-loss drug
To maximize the effectiveness of weight-loss medication, several
key concepts should be kept in mind and communicated to patients
before initiation of treatment.
Realistic weight-loss expectations
One of the greatest challenges in medical management of obesity
is to communicate to patients the amount of weight loss that can
be realistically expected from any weight management intervention.
Most patients come to their physician with unrealistic expectations.
When asked, they usually report wanting to lose 30% of their initial
body weight. This degree of weight loss is not currently achievable
by most patients except perhaps with restrictive gastric surgery.
However, weight-loss medications can help many obese patients
achieve a medically significant reduction. A 5% to 10% weight
loss can improve hypertension, lipid levels, and blood glucose
levels and can prevent health-related complications of obesity.
Weight-loss goals should be discussed with the patient and realistic
expectations established as early as possible. It is also important
to focus on nonweight outcomes, to discuss the potential for physiologic
limits, and to be empathetic. One approach is to set an initial
goal of 10% weight loss with the idea that a second goal can be
set when the first one is achieved. Long-term maintenance of a
10% weight loss should be seen as success by both the physician
and the patient.
Importance of long-term use
For maximum effectiveness, use of weight-loss medications and
obesity treatment in general must be thought of as long-term therapy.
As with medications for diabetes and hypertension, the benefits
from weight-loss medications disappear when the treatment is discontinued.
This need for long-term treatment should be discussed with the
patient. Obesity is a chronic metabolic disorder, and in most
cases, medications need to be taken as an adjunct to lifestyle
change as long as the patient wants to maintain the reduction
in body weight.
Adjunct to lifestyle change
Another fundamental concept to communicate to patients is the
importance of the interaction between drug and behavior. For weight-loss
drugs to work, the pharmacologic action must be translated into
behavior. For example, a sense of decreased hunger should result
in smaller meals or fewer snacks. Failure to act on such signals
results in little or no weight loss.
The current weight-loss medications work best when combined with
a specific plan to alter lifestyle behaviors, such as reducing
intake and increasing physical activity. These medications are
not designed to work alone; rather, they maximize the patient's
efforts to lose weight. When there is little or no planned effort,
there is little to maximize. If the patient has a plan to reduce
portions at each meal, the medication will help make it easier
to do this, but it will not have much effect if he or she does
not actually eat less. Therefore, obesity medications should be
prescribed as an adjunct to, not a substitute for, lifestyle change.
Summary
Obesity is a chronic medical disorder that is not going away anytime
soon. Physicians need all the education, tools, and resources
possible to successfully help their overweight and obese patients.
Weight-loss medications alone are clearly not the answer. However,
they are one tool physicians can use in combination with lifestyle
changes to increase the success of long-term weight loss in selected
patients.
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