The Management of Obesity for the Primary Care Physician

At this year’s meeting of the American College of Gastroenterology, a symposium on the management of obesity was held. The slant was toward what gastroenterologists can do, but, clearly, the talks have an impact on the interdisciplinary role needed for clinicians to deal with this growing American problem. The talks were classified into 3 general areas: medical management, surgical management, and management of bariatric surgery complications.

Medical Management of Obesity

Almost 65% of Americans are either overweight or obese. After smoking, obesity is the second most preventable cause of death in our country.

Obesity is also rampant in our children, who comprise the fastest-growing group becoming overweight or obese. There are many reasons to reduce this epidemic. Among them are that obese individuals have a higher rate of cancer and that the costs to care for obese patients are about 38% higher than the costs of caring for nonobese patients.

Many GI problems exist in the obese population that need care, including gallbladder disease, pancreatitis, reflux, and liver disease. Of note is that obesity-related liver disease (nonalcoholic fatty liver disease) is likely to become a major indication for liver transplantation in the very near future. Also, for those individuals who undergo surgical treatment of obesity, there will be a need for physicians to provide postoperative care.

Many individuals would like to blame their genetic makeup for their weight problems; however, only 40% of the tendency to be overweight comes from what is inherited. It appears that the environment has a major input. Higher caloric intake with less energy expended is a formula for weight gain.

The first thing that patients and physicians alike must understand is that obesity is a chronic problem. Unfortunately, we have not been as successful in treating this problem as we have in treating hypertension or hyperlipidemia. Office or hospital evaluations should begin with the determination of the body mass index (BMI), which is usually a good indicator of excess body fat. Note that individuals with excess muscle mass may have a BMI suggesting obesity. Also, some people with BMI in the normal range may have reduced muscle mass and excess fat.

Table 1 shows the derivation of the BMI. However, it is much easier to use tables, wall charts, or calculations done on your personal digital assistants.

Table 1. Body Mass Index Calculation and Meaning

BMI = Weight (kg)/height2 m2)

Overweight: BMI = 25.0-29.9

Obese: BMI >/=30

One reason why it is difficult to treat obesity is that people set unrealistic goals. For most individuals who are not contemplating surgery, an initial weight-loss goal should be between 5% and 10% of the starting weight. Clearly, for most people this could represent a very small amount; however, this strategy has the advantage of not only being achievable by most people, but also represents a weight loss associated with an amelioration of many medical problems.

At any one time, about 45% of US women and 30% of US men are trying to lose weight. The management of obesity may consist of the following: diet, exercise, behavior modification, pharmacologic interventions, and/or surgery. The mainstay of any weight-loss regimen is a reduced calorie intake, or weight-loss diet. There have been many controversies over the years about which “diet” is best. Unfortunately, the jury is still out. Low carbohydrates compared with high carbohydrates or low-fat diets are now being more rigorously investigated, but the bottom line is the same - reduce the caloric intake to help lose weight. Referring patients to a registered dietitian can help direct them toward a better dietary plan.

Much emphasis is placed on exercise, and deservedly so - it is an important component of an approach to losing weight. For most individuals, walking is fine. Start slow, and gradually add time and increase the speed. If orthopaedic issues are a problem, then swimming or other activities may be useful. It has been shown that adherence to an exercise program can predict the long-term maintenance of a person’s weight loss. Availability of an exercise physiologist or personal trainer may be beneficial.

Behavior modification can be helpful in teaching patients why they turn to food for comfort or in teaching strategies for changing eating behavior. By itself, it may have a very small effect, but as part of a weight-loss program, behavior modification can have a more additive effect.

Unlike hypertension, diabetes, or hyperlipidemia, for which there is a plethora of medications, the medical treatment of obesity is limited to very few specific medications. Table 2 lists the current medications that are FDA-approved for the treatment of obesity. Of these medications, only 2, sibutramine and orlistat, are FDA-approved for up to 2 years of use. The other medications that are effective - phentermine, phendimetrazine, and diethylpropion - are labeled for short-term use, meaning up to 12 weeks. This equates to a short-term fix for a long-term problem. Side effects for all of the drugs listed in Table 2 except orlistat commonly include elevation of blood pressure, tachycardia, central nervous system overstimulation, dry mouth, and, rarely, memory loss. Their use should be avoided in patients with advanced arteriosclerosis and uncontrolled hypertension, as myocardial infarctions and strokes can occur. Also, avoid these medications within 14 days of taking monoamine oxidase (MAO) inhibitor medications. Phentermines have been used very successfully in helping to reduce weight, but their long-term use must be readdressed.

Table 2. Current Pharmacologic Options

NS = Not scheduled
aGate Pharmaceuticals, North Wales, Pennsylvania
bCelltech Pharmaceuticals, Rochester, New York
cRoxane Laboratories, Columbus, Ohio
dAmarin Pharmaceuticals, Mill Valley, California
eAventis Pharmaceuticals, Bridgewater, New Jersey
fAbbott Laboratories, North Chicago, Ilinois
gRoche Laboratories, Nutley, New Jersey

Orlistat is unique in that it is a lipase inhibitor and will block about one third of ingested fat. Its mode of action thereby leads to GI side effects such as oily discharge or loose stools. These can be minimized by the use of psyllium.

There are many other medications being evaluated at the present time, but their approval for common use may be years away. Surgical options remain very effective methods of weight loss and must be put into the proper perspective. However, our country needs to consider that the prevention of obesity may be its best treatment.

Surgical Management of Obesity

If weight loss is beneficial to the treatment of obesity, then surgical intervention can deliver results. Why are people interested in surgery as an option? There are many reasons why the public is interested, such as the availability of a laparoscopic approach, published outcomes data, access to Internet information, positive family and peer experiences with surgery, positive celebrity experiences with surgery, and the media attention to surgical choices and their risks.

Foremost, there are successful data. A National Institutes of Health (NIH) consensus conference was held in 1990 and concluded that bariatric surgery was appropriate for individuals with a BMI *gt;/= 40 or a BMI >/= 35 if there are significant comorbidities. The goals of surgical treatment are to induce and maintain significant loss of excess weight through a safe operation, to ameliorate or resolve the chronic health conditions associated with obesity, and to improve the quality of life. Pathophysiologically, all bariatric surgical procedures create either intestinal malabsorption or gastric restriction, or a combination of both. Patients should be well-informed, highly motivated individuals who have acceptable surgical-risk profiles. Selection of patients should occur through a multidisciplinary approach that includes medical, surgical, psychiatric, and nutritional expertise. Patients should choose an experienced surgeon who has multidisciplinary support and who is capable of lifelong medical surveillance.

The preoperative patient evaluation should include a thorough assessment of the individual patient with a careful history, comprehensive physical exam, and detailed lab testing, with additional emphasis on informed consent and patient education. The goal is to evaluate all medical comorbidities, but these do not disqualify most patients. Common obesity-related comorbid conditions that are often diagnosed by the surgeon include the following: obstructive sleep apnea syndrome, coronary artery occlusive disease, Deep venous thrombosis and/or pulmonary thromboembolism, history of blood-clotting abnormalities, and neurologic conditions such as pseudotumor cerebri. The usual age range for this surgery has traditionally been 18-50 years of age, but there are now emerging data for teenagers aged 12-17 and older patients aged 50-75 years.

Table 3 lists the currently performed surgical procedures for obesity. The surgical focus now is on the ability to operate laparoscopically because of decreased disability and morbidity. The 2 primary procedures that are being performed are the laparoscopic adjustable gastric banding (Lap-Band) and the laparoscopic proximal gastric bypass (also called the Roux-en-Y proximal gastric bypass). There are no prospective randomized, controlled trials of the Lap-Band procedure, but rather only data from prospective database reviews.  The Lap-Band procedure has also been criticized for a high failure rate and poor results in African-Americans. The Lap-Band is a restrictive procedure and can be defeated by eating high-calorie sweets, and there are surgical learning-curve issues regarding band placement and management. The current recommendation is that the Lap-Band needs more study before universal use in the United States.

Provided by ArmMed Media
Revision date: July 7, 2011
Last revised: by David A. Scott, M.D.