Evaluation and Management of Obesity

Fast food behind Obese

Evaluation and Management of Obesity: Introduction

Over 66% of U.S. adults are currently categorized as overweight or obese, and the prevalence of obesity is increasing rapidly throughout most of the industrialized world. Based on statistics from the World Health Organization, overweight and obesity may soon replace more traditional public health concerns such as undernutrition and infectious diseases as the most significant contributors to ill health. Children and adolescents are also becoming more obese, indicating that the current trends will accelerate over time. Obesity is associated with an increased risk of multiple health problems, including hypertension, type 2 diabetes, dyslipidemia, degenerative joint disease, and some malignancies. Thus, it is important for physicians to routinely identify, evaluate, and treat patients for obesity and associated comorbid conditions.

Evaluation The U.S. Preventive Services Task Force recommends that physicians screen all adult patients for obesity and offer intensive counseling and behavioral interventions to promote sustained weight loss. This recommendation is consistent with previously released guidelines from the National Heart, Lung, and Blood Institute (NHLBI) and a number of medical societies. The five main steps in the evaluation of obesity are described below and include (1) focused obesity-related history, (2) physical examination to determine the degree and type of obesity, (3) comorbid conditions, (4) fitness level, and (5) the patient's readiness to adopt lifestyle changes. The Obesity-Focused History Information from the history should address the following six questions: What factors contribute to the patient's obesity? How is the obesity affecting the patient's health? What is the patient's level of risk from obesity? What are the patient's goals and expectations? Is the patient motivated to begin a weight management program? What kind of help does the patient need? Although the vast majority of obesity can be attributed to behavioral features that affect diet and physical activity patterns, the history may suggest secondary causes that merit further evaluation. Disorders to consider include polycystic ovarian syndrome, hypothyroidism, Cushing's syndrome, and hypothalamic disease. Drug-induced weight gain should also to be considered. Common causes include antidiabetes agents (insulin, sulfonylureas, thiazolidinediones); steroid hormones; psychotropic agents; mood stabilizers (lithium); antidepressants (tricyclics, monoamine oxidase inhibitors, paraxetine, mirtazapine); and antiepileptic drugs (valproate, gabapentin, carbamazapine). Other medications such as nonsteroidal anti-inflammatory drugs and calcium-channel blockers may cause peripheral edema, but they do not increase body fat. The patient's current diet and physical activity patterns may reveal factors that contribute to the development of obesity in addition to identifying behaviors to target for treatment. This type of historical information is best obtained by using a questionnaire in combination with an interview. BMI and Waist Circumference Three key anthropometric measurements are important to evaluate the degree of obesity—weight, height, and waist circumference. The body mass index (BMI), calculated as weight (kg)/height (m)2, or as weight (lbs)/height (inches)2 x 703, is used to classify weight status and risk of disease (Tables 75-1 and 75-2). BMI is used since it provides an estimate of body fat and is related to risk of disease. Lower BMI thresholds for overweight and obesity have been proposed for the Asia-Pacific region since this population appears to be at-risk at lower body weights for glucose and lipid abnormalities.  Body Mass Index (BMI) Table BMI 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 Height, inches Body Weight, pounds 58 91 96 100 105 110 115 119 124 129 134 138 143 148 153 158 162 167 59 94 99 104 109 114 119 124 128 133 138 143 148 153 158 163 168 173 60 97 102 107 112 118 123 128 133 138 143 148 153 158 163 168 174 179 61 100 106 111 116 122 127 132 137 143 148 153 158 164 169 174 180 185 62 104 109 115 120 126 131 136 142 147 153 158 164 169 175 180 186 191 63 107 113 118 124 130 135 141 146 152 158 163 169 175 180 186 191 197 64 110 116 122 128 134 140 145 151 157 163 169 174 180 186 192 197 204 65 114 120 126 132 138 144 150 156 162 168 174 180 186 192 198 204 210 66 118 124 130 136 142 148 155 161 167 173 179 186 192 198 204 210 216 67 121 127 134 140 146 153 159 166 172 178 185 191 198 204 211 217 223 68 125 131 138 144 151 158 164 171 177 184 190 197 203 210 216 223 230 69 128 135 142 149 155 162 169 176 182 189 196 203 209 216 223 230 236 70 132 139 146 153 160 167 174 181 188 195 202 209 216 222 229 236 243 71 136 143 150 157 165 172 179 186 193 200 208 215 222 229 236 243 250 72 140 147 154 162 169 177 184 191 199 206 213 221 228 235 242 250 258 73 144 151 159 166 174 182 189 197 204 212 219 227 235 242 250 257 265 74 148 155 163 171 179 186 194 202 210 218 225 233 241 249 256 264 272 75 152 160 168 176 184 192 200 208 216 224 232 240 248 256 264 272 279 76 156 164 172 180 189 197 205 213 221 230 238 246 254 263 271 279 287 BMI 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 58 172 177 181 186 191 196 201 205 210 215 220 224 229 234 239 244 248 253 258 59 178 183 188 193 198 203 208 212 217 222 227 232 237 242 247 252 257 262 267 60 184 189 194 199 204 209 215 220 225 230 235 240 245 250 255 261 266 271 276 61 190 195 201 206 211 217 222 227 232 238 243 248 254 259 264 269 275 280 285 62 196 202 207 213 218 224 229 235 240 246 251 256 262 267 273 278 284 289 295 63 203 208 214 220 225 231 237 242 248 254 259 265 270 278 282 287 293 299 304 64 209 215 221 227 232 238 244 250 256 262 267 273 279 285 291 296 302 308 314 65 216 222 228 234 240 246 252 258 264 270 276 282 288 294 300 306 312 318 324 66 223 229 235 241 247 253 260 266 272 278 284 291 297 303 309 315 322 328 334 67 230 236 242 249 255 261 268 274 280 287 293 299 306 312 319 325 331 338 344 68 236 243 249 256 262 269 276 282 289 295 302 308 315 322 328 335 341 348 354 69 243 250 257 263 270 277 284 291 297 304 311 318 324 331 338 345 351 358 365 70 250 257 264 271 278 285 292 299 306 313 320 327 334 341 348 355 362 369 376 71 257 265 272 279 286 293 301 308 315 322 329 338 343 351 358 365 372 379 386 72 265 272 279 287 294 302 309 316 324 331 338 346 353 361 368 375 383 390 397 73 272 280 288 295 302 310 318 325 333 340 348 355 363 371 378 386 393 401 408 74 280 287 295 303 311 319 326 334 342 350 358 365 373 381 389 396 404 412 420 75 287 295 303 311 319 327 335 343 351 359 367 375 383 391 399 407 415 423 431 76 295 304 312 320 328 336 344 353 361 369 377 385 394 402 410 418 426 435 443  Classification of Weight Status and Risk of Disease BMI (kg/m2) Obesity Class Risk of Disease Underweight <18.5 Healthy weight 18.5–24.9 Overweight 25.0–29.9 Increased Obesity 30.0–34.9 I High Obesity 35.0–39.9 II Very high Extreme Obesity 40 III Extremely high Source: Adapted from National Institutes of Health, National Heart, Lung, and Blood Institute: Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults. U.S. Department of Health and Human Services, Public Health Service, 1998. Excess abdominal fat, assessed by measurement of waist circumference or waist-to-hip ratio, is independently associated with higher risk for diabetes mellitus and cardiovascular disease. Measurement of the waist circumference is a surrogate for visceral adipose tissue and should be performed in the horizontal plane above the iliac crest. Cut points that define higher risk for men and women based on ethnicity have been proposed by the International Diabetes Federation .  Ethnic-Specific Values for Waist Circumference Ethnic Group Waist Circumference Europeans   Men >94 cm (37 in)   Women >80 cm (31.5 in) South Asians and Chinese   Men >90 cm (35 in)   Women >80 cm (31.5 in) Japanese   Men >85 cm (33.5 in)   Women >90 cm (35 in) Ethnic south and central Americans Use south Asian recommendations until more specific data are available. Sub-Saharan Africans Use European data until more specific data are available. Eastern Mediterranean and Middle East (Arab) populations Use European data until more specific data are available. Source: From KGMM Alberti et al for the IDF Epidemiology Task Force Consensus Group: The metabolic syndrome—a new worldwide definition. Lancet 366:1059, 2005. Physical Fitness Several prospective studies have demonstrated that physical fitness, reported by questionnaire or measured by a maximal treadmill exercise test, is an important predictor of all-cause mortality independent of BMI and body composition. These observations highlight the importance of taking an exercise history during examination as well as emphasizing physical activity as a treatment approach. Obesity-Associated Comorbid Conditions The evaluation of comorbid conditions should be based on presentation of symptoms, risk factors, and index of suspicion. All patients should have a fasting lipid panel (total, LDL, and HDL cholesterol and triglyceride levels) and blood glucose measured at presentation along with blood pressure determination. Symptoms and diseases that are directly or indirectly related to obesity are listed in Table. Although individuals vary, the number and severity of organ-specific comorbid conditions usually rise with increasing levels of obesity. Patients at very high absolute risk include the following: established coronary heart disease; presence of other atherosclerotic diseases such as peripheral arterial disease, abdominal aortic aneurysm, and symptomatic carotid artery disease; type 2 diabetes; and sleep apnea. Obesity-Related Organ Systems Review Cardiovascular  Respiratory    Hypertension   Dyspnea   Congestive heart failure   Obstructive sleep apnea   Cor pulmonale   Hypoventilation syndrome   Varicose veins   Pickwickian syndrome   Pulmonary embolism   Asthma   Coronary artery disease Gastrointestinal  Endocrine    Gastroesophageal reflux disease   Metabolic syndrome   Nonalcoholic fatty liver disease   Type 2 diabetes   Cholelithiasis   Dyslipidemia   Hernias   Polycystic ovarian syndrome   Colon cancer Musculoskeletal  Genitourinary    Hyperuricemia and gout   Urinary stress incontinence   Immobility   Obesity-related glomerulopathy   Osteoarthritis (knees and hips)   Hypogonadism (male)   Low back pain   Breast and uterine cancer   Carpal tunnel syndrome   Pregnancy complications Psychological  Neurologic    Depression/low self-esteem   Stroke   Body image disturbance   Idiopathic intracranial hypertension   Social stigmatization   Meralgia paresthetica Integument    Dementia   Striae distensae   Stasis pigmentation of legs   Lymphedema   Cellulitis   Intertrigo, carbuncles   Acanthosis nigricans   Acrochordon (skin tags)   Hidradenitis suppurativa Assessing the Patient's Readiness to Change An attempt to initiate lifestyle changes when the patient is not ready usually leads to frustration and may hamper future weight-loss efforts. Assessment includes patient motivation and support, stressful life events, psychiatric status, time availability and constraints, and appropriateness of goals and expectations. Readiness can be viewed as the balance of two opposing forces: (1) motivation, or the patient's desire to change; and (2) resistance, or the patient's resistance to change. A helpful method to begin a readiness assessment is to "anchor" the patient's interest and confidence to change on a numerical scale. Using this technique, the patient is asked to rate his or her level of interest and confidence on a scale from 0 to 10, with 0 being not so important (or confident) and 10 being very important (or confident) to lose weight at this time. This exercise helps to establish readiness to change and also serves as a basis for further dialogue.

Obesity: Treatment The Goal of Therapy The primary goal of treatment is to improve obesity-related comorbid conditions and reduce the risk of developing future comorbidities. Information obtained from the history, physical examination, and diagnostic tests is used to determine risk and develop a treatment plan . The decision of how aggressively to treat the patient, and which modalities to use, is determined by the patient's risk status, expectations, and available resources. Therapy for obesity always begins with lifestyle management and may include pharmacotherapy or surgery, depending on BMI risk category . Setting an initial weight-loss goal of 10% over 6 months is a realistic target. Treatment algorithm. This algorithm applies only to the assessment for overweight and obesity and subsequent decisions on that assessment. It does not reflect any initial overall assessment for other conditions that the physician may wish to perform. Ht, height; Hx, history; Wt, weight. (From National, Heart, Lung, and Blood Institute: Clinical guidelines on the identification, evaluation, and treatment of overweight and obesity in adults: The evidence report. Washington, DC, US Department of Health and Human Services, 1998.)  A Guide to Selecting Treatment BMI Category Treatment 25–26.9 27–29.9 30–35 35–39.9 40 Diet, exercise, behavior therapy With comorbidities With comorbidities + + + Pharmacotherapy With comorbidities + + + Surgery With comorbidities + Source: From National Heart, Lung, and Blood Institute, North American Association for the Study of Obesity (2000). Lifestyle Management Obesity care involves attention to three essential elements of lifestyle: dietary habits, physical activity, and behavior modification. Because obesity is fundamentally a disease of energy imbalance, all patients must learn how and when energy is consumed (diet), how and when energy is expended (physical activity), and how to incorporate this information into their daily life (behavior therapy). Lifestyle management has been shown to result in a modest (typically 3–5 kg) weight loss compared to no treatment or usual care. Diet Therapy The primary focus of diet therapy is to reduce overall calorie consumption. The NHLBI guidelines recommend initiating treatment with a calorie deficit of 500–1000 kcal/d compared to the patient's habitual diet. This reduction is consistent with a goal of losing approximately 1–2 lb per week. This calorie deficit can be accomplished by suggesting substitutions or alternatives to the diet. Examples include choosing smaller portion sizes, eating more fruits and vegetables, consuming more whole-grain cereals, selecting leaner cuts of meat and skimmed dairy products, reducing fried foods and other added fats and oils, and drinking water instead of caloric beverages. It is important that the dietary counseling remains patient-centered and that the goals are practical, realistic, and achievable. The macronutrient composition of the diet will vary depending on the patient's preference and medical condition. The 2005 U.S. Department of Agriculture Dietary Guidelines for Americans (Chap. 70), which focus on health promotion and risk reduction, can be applied to treatment of the overweight or obese patient. The recommendations include maintaining a diet rich in whole grains, fruits, vegetables, and dietary fiber; consuming two servings (8 oz) of fish high in omega 3 fatty acids per week; decreasing sodium to <2300 mg/d; consuming 3 cups of milk (or equivalent low-fat or fat-free dairy products) per day; limiting cholesterol to <300 mg/d; and keeping total fat between 20 and 35% of daily calories and saturated fats to <10% of daily calories. Application of these guidelines to specific calorie goals can be found on the website www.mypyramid.gov. The revised Dietary Reference Intakes for Macronutrients released by the Institute of Medicine recommends 45–65% of calories from carbohydrates, 20–35% from fat, and 10–35% from protein. The guidelines also recommend daily fiber intake of 38 g (men) and 25 g (women) for persons over 50 years of age and 30 g (men) and 21 g (women) for those under 50. Since portion control is one of the most difficult strategies for patients to manage, the use of pre-prepared products, such as meal replacements, is a simple and convenient suggestion. Examples include frozen entrees, canned beverages and bars. Use of meal replacements in the diet has been shown to result in a 7–8% weight loss. A current area of controversy is the use of low-carbohydrate, high-protein diets for weight loss. These diets are based on the concept that carbohydrates are the primary cause of obesity and lead to insulin resistance. Most low-carbohydrate diets (e.g., South Beach, Zone, and Sugar Busters!) recommend a carbohydrate level of approximately 40–46% of energy. The Atkins diet contains 5–15% carbohydrate, depending on the phase of the diet. Several randomized, controlled trials of these low-carbohydrate diets have demonstrated greater weight loss at 6 months with improvement in coronary heart disease risk factors, including an increase in HDL cholesterol and a decrease in triglyceride levels. Weight loss between groups did not remain statistically significant at 1 year; however, low-carbohydrate diets appear to be at least as effective as low-fat diets in inducing weight loss for up to 1 year. Another dietary approach to consider is the concept of energy density, which refers to the number of calories (energy) a food contains per unit of weight. People tend to ingest a constant volume of food, regardless of caloric or macronutrient content. Adding water or fiber to a food decreases its energy density by increasing weight without affecting caloric content. Examples of foods with low-energy density include soups, fruits, vegetables, oatmeal, and lean meats. Dry foods and high-fat foods such as pretzels, cheese, egg yolks, potato chips, and red meat have a high-energy density. Diets containing low-energy dense foods have been shown to control hunger and result in decreased caloric intake and weight loss. Occasionally, very-low-calorie diets (VLCDs) are prescribed as a form of aggressive dietary therapy. The primary purpose of a VLCD is to promote a rapid and significant (13–23 kg) short-term weight loss over a 3–6 month period. These propriety formulas typically supply 800 kcal, 50–80 g protein, and 100% of the recommended daily intake for vitamins and minerals. According to a review by the National Task Force on the Prevention and Treatment of Obesity, indications for initiating a VLCD include well-motivated individuals who are moderately to severely obese (BMI >30), have failed at more conservative approaches to weight loss, and have a medical condition that would be immediately improved with rapid weight loss. These conditions include poorly controlled type 2 diabetes, hypertriglyceridemia, obstructive sleep apnea, and symptomatic peripheral edema. The risk for gallstone formation increases exponentially at rates of weight loss >1.5 kg/week (3.3 lb/week). Prophylaxis against gallstone formation with ursodeoxycholic acid, 600 mg/d, is effective in reducing this risk. Because of the need for close metabolic monitoring, these diets are usually prescribed by physicians specializing in obesity care. Physical Activity Therapy Although exercise alone is only moderately effective for weight loss, the combination of dietary modification and exercise is the most effective behavioral approach for the treatment of obesity. The most important role of exercise appears to be in the maintenance of the weight loss. Currently, the minimum public health recommendation for physical activity is 30 min of moderate intensity physical activity on most, and preferably all, days of the week. Focusing on simple ways to add physical activity into the normal daily routine through leisure activities, travel, and domestic work should be suggested. Examples include walking, using the stairs, doing home and yard work, and engaging in sport activities. Asking the patient to wear a pedometer to monitor total accumulation of steps as part of the activities of daily living is a useful strategy. Step counts are highly correlated with activity level. Studies have demonstrated that lifestyle activities are as effective as structured exercise programs for improving cardiorespiratory fitness and weight loss. The Dietary Guidelines for Americans 2005 summarizes compelling evidence that at least 60–90 min of daily moderate-intensity physical activity (420–630 min per week) is needed to sustain weight loss (http://www.health.gov/dietaryguidelines/dga2005/). The American College of Sports Medicine recommends that overweight and obese individuals progressively increase to a minimum of 150 min of moderate intensity physical activity per week as a first goal. However, for long-term weight loss, a higher level of exercise (e.g., 200–300 min or 2000 kcal per week) is needed. These recommendations are daunting to most patients and need to be implemented gradually. Consultation with an exercise physiologist or personal trainer may be helpful. Behavioral Therapy Cognitive behavioral therapy is used to help change and reinforce new dietary and physical activity behaviors. Strategies include self-monitoring techniques (e.g., journaling, weighing, and measuring food and activity); stress management; stimulus control (e.g., using smaller plates, not eating in front of the television or in the car); social support; problem solving; and cognitive restructuring to help patients develop more positive and realistic thoughts about themselves. When recommending any behavioral lifestyle change, have the patient identify what, when, where, and how the behavioral change will be performed. The patient should keep a record of the anticipated behavioral change so that progress can be reviewed at the next office visit. Because these techniques are time-consuming to implement, they are often provided by ancillary office staff such as a nurse clinician or registered dietitian. Pharmacotherapy Adjuvant pharmacologic treatments should be considered for patients with a BMI >30 kg/m2 or with a BMI >27 kg/m2 who also have concomitant obesity-related diseases and for whom dietary and physical activity therapy has not been successful. When prescribing an antiobesity medication, patients should be actively engaged in a lifestyle program that provides the strategies and skills needed to effectively use the drug since this support increases total weight loss. There are several potential targets of pharmacologic therapy for obesity. The most thoroughly explored treatment is suppression of appetite via centrally active medications that alter monoamine neurotransmitters. A second strategy is to reduce the absorption of selective macronutrients from the gastrointestinal (GI) tract, such as fat. These two mechanisms form the basis for all currently prescribed antiobesity agents. A third target, selective blocking of the endocannabinoid system, has recently been identified. Centrally Acting Anorexiant Medications Appetite-suppressing drugs, or anorexiants, affect satiety—the absence of hunger after eating—and hunger—a biologic sensation that initiates eating. By increasing satiety and decreasing hunger, these agents help patients reduce caloric intake without a sense of deprivation. The target site for the actions of anorexiants is the ventromedial and lateral hypothalamic regions in the central nervous system (Chap. 74). Their biological effect on appetite regulation is produced by augmenting the neurotransmission of three monoamines: norepinephrine; serotonin [5-hydroxytryptamine (5-HT)]; and, to a lesser degree, dopamine. The classic sympathomimetic adrenergic agents (benzphetamine, phendimetrazine, diethylpropion, mazindol, and phentermine) function by stimulating norepinephrine release or by blocking its reuptake. In contrast, sibutramine (Meridia) functions as a serotonin and norepinephrine reuptake inhibitor. Unlike other previously used anorexiants, sibutramine is not pharmacologically related to amphetamine and has no addictive potential. Sibutramine is the only anorexiant that is currently approved by the Food and Drug Administration (FDA) for long-term use. It produces an average loss of about 5–9% of initial body weight at 12 months. Sibutramine has been demonstrated to maintain weight loss for up to 2 years. The most commonly reported adverse events of sibutramine are headache, dry mouth, insomnia, and constipation. These are generally mild and well-tolerated. The principal concern is a dose-related increase in blood pressure and heart rate that may require discontinuation of the medication. A dose of 10–15 mg/d causes an average increase in systolic and diastolic blood pressure of 2–4 mmHg and an increase in heart rate of 4–6 beats/min. For this reason, all patients should be monitored closely and evaluated within 1 month after initiating therapy. The risk of adverse effects on blood pressure are no greater in patients with controlled hypertension than in those who do not have hypertension, and the drug does not appear to cause cardiac valve dysfunction. Contraindications to sibutramine use include uncontrolled hypertension, congestive heart failure, symptomatic coronary heart disease, arrhythmias, or history of stroke. Similar to other antiobesity medications, weight reduction is enhanced when the drug is used along with behavioral therapy, and body weight increases when the medication is discontinued. Peripherally Acting Medications Orlistat (Xenical) is a synthetic hydrogenated derivative of a naturally occurring lipase inhibitor, lipostatin, produced by the mold Streptomyces toxytricini. Orlistat is a potent, slowly reversible inhibitor of pancreatic, gastric, and carboxylester lipases and phospholipase A2, which are required for the hydrolysis of dietary fat into fatty acids and monoacylglycerols. The drug acts in the lumen of the stomach and small intestine by forming a covalent bond with the active site of these lipases. Taken at a therapeutic dose of 120 mg tid, orlistat blocks the digestion and absorption of about 30% of dietary fat. After discontinuation of the drug, fecal fat usually returns to normal concentrations within 48–72 h. Multiple randomized, 1–2 year double-blind, placebo-controlled studies have shown that after one year, orlistat produces a weight loss of about 9–10%, compared with a 4–6% weight loss in the placebo-treated groups. Because orlistat is minimally (<1%) absorbed from the GI tract, it has no systemic side effects. Tolerability to the drug is related to the malabsorption of dietary fat and subsequent passage of fat in the feces. GI tract adverse effects are reported in at least 10% of orlistat-treated patients. These include flatus with discharge, fecal urgency, fatty/oily stool, and increased defecation. These side effects are generally experienced early, diminish as patients control their dietary fat intake, and infrequently cause patients to withdraw from clinical trials. Psyllium mucilloid is helpful in controlling the orlistat-induced GI side effects when taken concomitantly with the medication. Serum concentrations of the fat-soluble vitamins D and E and –carotene may be reduced, and vitamin supplements are recommended to prevent potential deficiencies. Orlistat was approved for other-the-counter use in 2007. The Endocannabinoid System Cannabinoid receptors and their endogenous ligands have been implicated in a variety of physiologic functions, including feeding, modulation of pain, emotional behavior, and peripheral lipid metabolism. Cannabis and its main ingredient, Δ9-tetrahydrocannabinol (THC), is an exogenous cannabinoid compound. Two endocannabinoids have been identified, anandamide and 2-arachidonyl glyceride. Two cannabinoid receptors have been identified: CB1 (abundant in the brain) and CB2 (present in immune cells). The brain endocannabinoid system is thought to control food intake through reinforcing motivation to find and consume foods with high incentive value and to regulate actions of other mediators of appetite. The first selective cannabinoid CB1 receptor antagonist, rimonabant, was discovered in 1994. The medication antagonizes the orexigenic effect of THC and suppresses appetite when given alone in animal models. Several large prospective, randomized controlled trials have demonstrated the effectiveness of rimonabant as a weight-loss agent. Taken as a 20 mg dose, subjects lost an average of 6.5 kg (14.32 lb) compared to 1.5 kg (3.3 lb) for placebo at 1 year. Concomitant improvements were seen in waist circumference and cardiovascular risk factors. The most common reported side effects include depression, anxiety, and nausea. FDA approval of Rimonabant is still pending. Surgery Bariatric surgery can be considered for patients with severe obesity (BMI 40 kg/m2) or those with moderate obesity (BMI 35 kg/m2) associated with a serious medical condition. Surgical weight loss functions by reducing caloric intake and, depending on the procedure, macronutrient absorption. Weight-loss surgeries fall into one of two categories: restrictive and restrictive-malabsorptive (Fig. 75-2). Restrictive surgeries limit the amount of food the stomach can hold and slow the rate of gastric emptying. The vertical banded gastroplasty (VBG) is the prototype of this category but is currently performed on a very limited basis due to lack of effectiveness in long-term trials. Laparoscopic adjustable silicone gastric banding (LASGB) has replaced the VBG as the most commonly performed restrictive operation. The first banding device, the lap-band, was approved for use in the United States in 2001. In contrast to previous devices, the diameter of this band is adjustable by way of its connection to a reservoir that is implanted under the skin. Injection or removal of saline into the reservoir tightens or loosens the band's internal diameter, thus changing the size of the gastric opening. The three restrictive-malabsorptive bypass procedures combine the elements of gastric restriction and selective malabsorption. These procedures include Roux-en-Y gastric bypass (RYGB), biliopancreatic diversion (BPD), and biliopancreatic diversion with duodenal switch (BPDDS) (Fig. 75-2). RYGB is the most commonly performed and accepted bypass procedure. It may be performed with an open incision or laparoscopically. Although no recent randomized controlled trials compare weight loss after surgical and nonsurgical interventions, data from meta-analyses and large databases, primarily obtained from observational studies, suggest that bariatric surgery is the most effective weight-loss therapy for those with clinically severe obesity. These procedures generally produce a 30–35% average total body weight loss that is maintained in nearly 60% of patients at 5 years. In general, mean weight loss is greater after the combined restrictive-malabsorptive procedures compared to the restrictive procedures. An abundance of data supports the positive impact of bariatric surgery on obesity-related morbid conditions, including diabetes mellitus, hypertension, obstructive sleep apnea, dyslipidemia, and nonalcoholic fatty liver disease. Surgical mortality from bariatric surgery is generally <1% but varies with the procedure, patient's age and comorbid conditions, and experience of the surgical team. The most common surgical complications include stomal stenosis or marginal ulcers (occurring in 5–15% of patients) that present as prolonged nausea and vomiting after eating or inability to advance the diet to solid foods. These complications are typically treated by endoscopic balloon dilatation and acid suppression therapy, respectively. For patients who undergo LASGB, there are no intestinal absorptive abnormalities other than mechanical reduction in gastric size and outflow. Therefore, selective deficiencies occur uncommonly unless eating habits become unbalanced. In contrast, the restrictive-malabsorptive procedures increase risk for micronutrient deficiencies of vitamin B12, iron, folate, calcium, and vitamin D. Patients with restrictive-malabsorptive procedures require lifelong supplementation with these micronutrients.