What are the clinical issues that need to be addressed during this preventive visit?A 20-year-old woman comes to clinic for an annual physical examination. She has no complaints. She has no significant medical or surgical history. She is currently taking oral contraceptive pills because of her irregular menstrual cycles. She attained menarche at age 13 years and has had irregular cycles since. She has never been sexually active. Her family history is positive for hypertension and obesity in both her parents. On examination, her blood pressure is 120/85 mm Hg, her pulse is 78 beats/min, and her respiratory rate is 14 breaths/min. Her weight is 188 lb and she is 63 in tall. Her physical examination is unremarkable except for a brownish/black, velvety thickening of the skin on the back of her neck, hirsutism, and abdominal obesity.
What are the clinical issues that need to be addressed during this preventive visit?
What is your next step in the evaluation of this patient?
What are the therapeutic options available for this patient?
Summary: A 20-year-old obese woman presents for a routine examination. Along with her abdominal obesity, she has irregular menstrual cycles, acanthosis nigricans, and hirsutism.
• Clinical issues to address: Obesity and possible polycystic ovarian disease.
• Next steps in evaluation: Calculate a body mass index (BMI), measure waist circumference, repeat blood pressure. Order laboratory tests to measure fasting glucose, lipids, thyroid-stimulating hormone (TSH), and liver enzymes.
• Therapeutic options: Assess her interest in losing weight. If she is interested, devise weight-loss goals and advise on diet and physical activity to achieve these goals. If she is not interested, advise on the health benefits of weight loss and address other risk factors. In either case, arrange follow-up. At subsequent visits, can consider adding pharmacotherapy as an adjunct to diet and exercise.
1. Understand the etiology and pathogenesis of obesity.
2. Know other comorbid conditions associated with obesity.
3. Learn the diagnostic criteria for obesity and the metabolic syndrome.
4. Understand the therapeutic options available for the management of obesity.
Obesity is a chronic and stigmatizing disease that begins early in life. Increased caloric intake, decreased physical exertion, and genetic predisposition are common causes of obesity. Routine physical examination visits serve as a good platform to address issues related to obesity and its associated comorbid conditions. In this case, this visit should be taken as an opportunity to address obesity, metabolic risk, and its management.
Increased body weight is a major risk factor for the development of disease and for premature death. In National Health and Nutritional Examination Surveys (NHANES) III, the metabolic syndrome presents in 5% of those at normal weight, 22% of those who were overweight, and 60% of those who were obese. The metabolic syndrome is an important risk factor for subsequent development of type 2 diabetes and cardiovascular disease (CVD).
In this case, this patient’s BMI is 33.5. Further measurements included a waist circumference of 36 in and a repeat blood pressure of 125/85 mm Hg. Her laboratory test results included total cholesterol of 202 mg/dL, high-density lipoprotein (HDL) cholesterol of 35 mg/dL, low-density lipoprotein (LDL) cholesterol of 120 mg/dL, and triglycerides of 172 mg/dL. Her fasting glucose was 104 mg/dL, and she had normal renal and liver function tests. She has metabolic syndrome based on her abdominal circumference, increased triglycerides, low HDL, and mildly elevated LDL cholesterol levels. She may also need further investigation for the presence of polycystic ovarian syndrome (PCOS) because of her obesity and history of irregular cycles.
Both the metabolic syndrome and PCOS are very closely associated with obesity and insulin resistance. In this situation, the key clinical implication of these diagnoses is identification of a patient needing aggressive lifestyle modification focused on weight reduction and increased physical activity.
BODY MASS INDEX (BMI): A measurement of the relative composition of lean body mass and body fat; calculated as weight in kilograms/(height in meters)2.
METABOLIC SYNDROME: An array of findings that describes a state of insulin resistance characterized by abdominal obesity, dyslipidemia, elevated blood pressure, and impaired fasting glucose.
OVERWEIGHT: Defined as BMI 25-29.9 kg/m2.
OBESITY: An excessive amount of body fat (defined as BMI of ≥30 kg/m2), which increases the risk of medical illness and premature death. Morbid obesity is defined as a BMI ≥40 kg/m2.
SATIATION: Level of fullness during a meal.
SATIETY: Level of hunger after a meal.
Obesity is a chronic and easily diagnosed disease that is associated with life-threatening morbidity and mortality. In the United States, data show that 32.2% of adult men, 35.5% of adult women, 17% of 6- to 11-year-olds, and 18% of 12- to 19-year-olds were obese. With an increasing prevalence in all age ranges, obesity is now considered to be a global epidemic. Approximately 365,000 deaths are attributed to obesity each year with the direct and indirect costs exceeding $100 billion per year.
BMI is used as a quick, easy, and reliable measure of overweight and obesity. It provides a more precise measure of total body fat compared with body weight alone. However, BMI is not as accurate a measure of overweight/obesity in patients with heart failure, pregnant women, body builders, professional athletes, elderly patients, and certain ethnic groups. Moreover, abdominal obesity is associated with increased risk for hypertension, heart disease, dyslipidemia, and diabetes. Additional measurements, like waist circumference, and waist-to-hip ratio, need to be used to accurately identify the population at risk. Direct measurement of percentage of body fat may also provide additional information. Table 33–1 lists the classification of overweight/obesity based on BMI.
Table 33–1 • DEFINITION OF OBESITY BASED ON BMI
Along with the measurements mentioned above, a health history, physical examination, and focused laboratory workup should be performed to look for complications and comorbid conditions. Any previous weight-loss efforts, recent smoking cessation, daily physical activity levels, and eating habits should be assessed to identify factors that might be contributing to weight gain and obesity. A fasting glucose level should be measured to evaluate for diabetes mellitus and impaired glucose tolerance. The presence of acanthosis nigricans—a velvety, hyperpigmented thickening of the skin commonly found on the neck and axillary regions—may also be a sign of insulin resistance. Fasting lipids should also be measured, both to evaluate for the presence of metabolic syndrome and for the assessment of the patient’s risk for cardiovascular disease. TSH should be measured to screen for hypothyroidism. Liver enzymes should be requested, as abnormal results may indicate the development of a fatty liver.
Energy balance is the relationship of energy intake to energy expenditure. When more energy is expended than taken in, weight loss ensues. When the intake of energy exceeds the amount expended, weight gain occurs. In all persons, obesity is caused by ingesting more energy than is expended over a period of time. Energy balance is affected by genetic, physiologic, and environmental factors.
It has been estimated that genetic background can explain 40% or more of the variance in body mass in humans. The genetic component is complex and involves the interaction of multiple genes. However, the marked increase in obesity cannot be completely attributed to genetics. Social factors such as lower education level, lower socioeconomic class, and cessation of smoking are all associated with high risk of obesity. Likewise, physiologic factors such as various gut hormones, level of spontaneous physical activity (fidgeting), and age-related decline in energy expenditure are key determinants in regulation of food intake and energy expenditure. An increase in energy consumption with a decrease in physical activity is thought to be the main contributor to the current obesity epidemic. Among numerous issues, the availability of convenience foods and the increase in palatability and serving size, compounded with industrialization leading to a sedentary lifestyle, has led to an altered energy balance.
Obesity is a risk factor for the development of numerous medical conditions (Table 33–2). In general, greater BMI is associated with more complications and greater risk of mortality. Also, the more complications that develop, the more difficult it becomes to manage the underlying obesity. For example, a person with degenerative arthritis and heart disease may have significant symptoms during exercise, impairing his or her ability to expend more energy in an effort to lose weight.
Table 33–2 • COMMON MEDICAL COMPLICATIONS OF OBESITY
Treatment of obesity should begin in patients with a BMI greater than 25 or who have visceral obesity, documented by increased waist circumference greater than 40 in men and greater than 35 in women or a waist-to-hip ratio greater than 0.9 in men and greater than 0.85 in women. Weight loss of as little as 5 lb reduces the risk of developing comorbid conditions. Developing a treatment plan for obesity is complex and should use a combination of dietary restrictions, increased physical activity, and behavior therapy as a gold standard.
Dietary intervention is the cornerstone of weight-loss therapy. Most diets work in two principal dimensions: energy content and nutrient composition. A calorie deficit of 500 to 1000 cal/d produces a weight loss of 1 to 2 lb/wk (0.45 to 0.91 kg/wk). Loss of more than 5% of initial body weight can improve CVD risk. There are different kinds of specific dietary modifications recommended, but they all work based on calorie restriction. The selection of a diet should be based upon patient preferences to promote optimal dietary adherence, a key determinant of weight loss irrespective of the type and nutrient composition of the diet. In addition, calorie restriction should not compromise the nutrient content of the diet; patients should still aim for a balanced meal.
The addition of exercise training to a diet program can add to the weight loss. However, physical activity alone is not an effective method for achieving weight loss. Although increasing physical activity is not effective for initial weight loss, physical activity is very important for long-term weight management and cardiovascular health benefits. Physical activity can improve insulin sensitivity and glycemic control, decrease abdominal fat, and reduce cardiovascular risk. Patients should engage in moderate to vigorous physical activity for at least 30 min/d, 5 to 7 d/wk, both to maintain weight loss and for the independent health benefits of exercising.
The purpose of behavior modification therapy is to help patients identify and make long-term changes in their eating and physical activity habits that contribute to obesity. The targets of behavior modification are avoiding triggers, maintaining dietary diaries, using portion-controlled plates, slowing rate of eating to enhance satiation, avoidance of high-risk situations, increasing physical activity, and breaking repetitive behaviors, such as watching TV while eating.
Table 33–3 lists the medications commonly used in the treatment of obesity. Pharmacologic therapy may be offered to those with a BMI greater than 30, or BMI of 27 to 30 with comorbid conditions. Only orlistat is approved for long-term use of up to 2 years by the US Food and Drug Administration (FDA).
Table 33–3 • MEDICATIONS USED IN THE TREATMENT OF OBESITY
With the exception of orlistat, which inhibits the absorption of dietary fat, all medications approved for obesity act as anorexiants. Anorexiant medications increase satiation, satiety, or both, by affecting the monoamine system in the hypothalamus. Increasing satiation results in a reduction in the amount of food eaten, whereas increasing satiety reduces the frequency of eating. The only FDA-approved class of anorexiant medications are the sympathomimetics such as phentermine, which is indicated for short-term use (a few weeks) in combination with diet, exercise, and behavioral treatments.
Metformin and exenatide, both approved for type 2 diabetes mellitus may be a useful adjunct for weight loss in patients with comorbid obesity. Metformin can also help with weight loss in patients with polycystic ovary syndrome.
There are other FDA-approved medications for mood disorders and epilepsy that may be associated with weight loss, but the studies are limited and the risk-to-benefit ratio has not been investigated. Many previously approved medications for weight loss have been removed from the market due to significant risks greater than benefits. Over-the-counter weight loss medications and supplements have similar risk benefit profiles or have limited research for safety and efficacy.
Patients with a BMI greater than 40 who have failed diet and exercise (with or without drug therapy), or greater than 35 with comorbid conditions, are potential candidates for surgical treatment of obesity. The two most common surgeries done are Roux-en-Y gastric bypass (RYGB) and laparoscopic adjustable gastric banding (LAGB) or “lap banding.” The RYGB involves the construction of a small (10-30 mL) gastric pouch that empties into a segment of jejunum. With the small pouch and the small outlet to limit caloric intake, the RYGB is mostly a restrictive procedure with some degree of associated malabsorption. In LAGB, an adjustable silicone gastric band is laparoscopically placed around the upper stomach just distal to the gastroesophageal junction. The band has a balloon connected to a subcutaneously implanted port, which can be inflated or deflated to reduce the circumference of the band. Complications of the banding procedure are less common and less severe than in gastric bypass, but the long-term weight loss may also be less. The adjustable band allows for the flexibility of addressing various nutritional demands after the surgery. For example, the band can be adjusted to have the stoma widened to accommodate a greater demand for caloric and fluid intake when a patient becomes pregnant.
Guidelines from the 2001 National Cholesterol Education Program (Adult Treatment Panel [ATP] III) suggest that the clinical identification of the metabolic syndrome should be based upon the presence of any three of the following traits:
1. Abdominal obesity, defined as a waist circumference in men greater than 102 cm (40 in) and in women greater than 88 cm (35 in). ATP III recognized that some men develop multiple metabolic risk factors when waist circumference is only marginally increased (94-102 cm [37-39 in]); such patients may have a genetic predisposition to insulin resistance.
2. Serum triglycerides greater than or equal to 150 mg/dL (1.7 mmol/L).
3. Serum high-density lipoprotein (HDL) cholesterol less than 40 mg/dL (1 mmol/L) in men and less than 50 mg/dL (1.3 mmol/L) in women.
4. Blood pressure greater than or equal to 130/85 mm Hg.
5. Fasting plasma glucose greater than or equal to 100 mg/dL (5.6 mmol/L).
Current minimum estimates are that the prevalence of metabolic syndrome in the United States is at least 34.5% using the ATP III criteria. The metabolic syndrome is an important risk factor for subsequent development of type 2 diabetes and cardiovascular disease. Thus, the key clinical implication of a diagnosis of metabolic syndrome is identification of a patient needing aggressive lifestyle modification focused on weight reduction and increased physical activity.
33.1 A 15-year-old adolescent male is brought in to the clinic by his mother. He has been experiencing chest pain, shortness of breath, and is having increased episodes of asthma exacerbation. He is 5ft 10 in and weighs 399 lb. An ECG in the office shows a normal sinus rhythm. He is unable to participate in school athletics due to his weight and has little physical activity after school. He has friends, but has some esteem issues because of being so large. He often finds it hard to find current trendy clothes in his size, but says it’s ok because he is not the largest person at his school. His mother, who is also morbidly obese, is worried that he will have a heart attack and wants him to lose weight. Which of the following patients would be a candidate for bariatric surgery as initial treatment for obesity?
A. A man with a BMI of 32 and arthritis of the knees.
B. A woman with a BMI of 30 and type 2 diabetes.
C. A woman with a BMI of 42 but no identifiable complications.
D. Any obese patient who desires bariatric surgery should have it offered.
33.2 A patient you have been seeing for 10 years recently lost his health insurance because his BMI is too high. He was born with achondroplasia and is 4 ft 8 in and 192 lb. He has been in good health and takes no medications. On examination his BP is 122/76 mm Hg, pulse 56 beats/min, and respiratory rate 16 breaths/min. For which of the following patients is a BMI measurement most likely to be an accurate assessment of obesity?
A. A bodybuilder with a BMI of 38
B. A pregnant woman with a BMI of 31 in her 37th week of gestation
C. A man with congestive heart failure, pitting edema, and a BMI of 30
D. A hypertensive woman with a BMI of 32
33.3 A 34-year-old Hispanic woman comes to clinic to discuss weight management. She is currently 5 ft 2 in and 265 lb. She says she always had a hard time managing her weight as a child, but let things get out of control when she was living on her own in college. She has had two children in the past 5 years. She gained 50 lb with the first child and lost 30 lb. With the second child she gained 35 lb and lost 10 lb. She has tried many fad diets where she initially loses weight but eventually gains it back. She exercises some but is limited by osteoarthritis of the knees. She has thought about gastric bypass but is fearful of undergoing a surgical procedure. Which of the following medications may be used for the long-term management of obesity?
A. Orlistat
B. Phendimetrazine
C. Dextroamphetamine
D. Phentermine
33.1 C. Bariatric surgery can be effective but carries significant risks. It is indicated for people with a BMI of greater than 40 who have failed diet and exercise (with or without drug therapy) or with a BMI of greater than 35 and obesity-related complications.
33.2 D. A BMI reading will not accurately assess the ratio of lean body mass to body fat in highly muscled persons (weightlifters, athletes), persons with decreased muscle mass (elderly), in pregnant women, and in symptomatic congestive heart failure.
33.3 A. Only orlistat is indicated for the long-term treatment of obesity. All of the other medications should be for short-term use only.
Obesity is a chronic disease that is reaching epidemic status in the United States and worldwide.
BMI is a common tool used to grade obesity, but in certain cases it may be inadequate.
Obesity treatment should always include dietary restriction, increased activity, and behavioral modifications.
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