Body fat percentage, body mass index, skin thicknesses, and anthropomorphic measures

Surgical therapy for obesity (bariatric surgery) is the only available therapeutic modality associated with clinically significant and sustained weight loss in subjects with morbid obesity associated with comorbidities. Evidence shows that well-performed bariatric surgery in carefully selected patients and a good multidisciplinary support team substantially ameliorates the morbidities associated with severe obesity. Although bariatric surgery is the only therapeutic method associated with consistently demonstrable sustained weight loss, it is expensive, highly procedure and surgeon specific, and certainly not the solution for the burgeoning obesity epidemic.

Patient selection for these procedures must be addressed along the same stringent lines as those discussed above for potential patients for medical weight-management programs (see Medical Care).

The presence of comorbidities is not a contraindication to these surgical procedures; however, the patient's condition must be stabilized and adequately treated before surgery. At a minimum, consider these procedures only in subjects with a BMI greater than 40 kg/m² and/or a weight greater than 45 kg above the age-defined and sex-defined ideal weight. For subjects with BMIs of 35-40 kg/m², several other comorbidities must be present to justify these procedures.

Among the comorbidities reported to be ameliorated and/or resolved by bariatric surgery are type 2 diabetes mellitus, hypertension, heart failure, peripheral edema, respiratory insufficiency, asthma, dyslipidemia, esophagitis, pseudotumor cerebri, sleep disorders, operative risk, osteoarthrosis, thromboembolism, and urinary incontinence. Other reports suggest improved quality of life and fertility among postsurgical patients. Although other outcomes are difficult to demonstrate and are awaiting clear documentation, these procedures may substantially reduce macrovascular complications (eg, myocardial infarction); stroke; amputations; obesity-related malignancies; and a predisposition to infection, hernias, and varicose veins.

Although most bariatric procedures were initially developed in the setting of laparotomies, they now are increasingly performed laparoscopically, with reduced postoperative morbidity. The laparoscopic approach to bariatric surgery is particularly well developed in Europe.

Among the standard bariatric procedures are (1) horizontal gastroplasty, (2) roux-en-Y gastric bypass, (3) biliopancreatic bypass, (4) silicone gastric banding, (5) adjustable gastric banding, (6) jejunoileal bypass procedures, and (7) biliopancreatic bypass with duodenal-switch procedures.

Although available data on the effectiveness of all these procedures are still relatively scant, anecdotal reports of individual patients and a few reports of the most commonly performed procedures (gastric restriction and gastric bypass procedures) lend veracity to the long-term effectiveness of bariatric surgery.

Ashley and colleagues (1993) examined 114 subjects who underwent vertical-band gastroplasty.^[55] About 60% lost more than 50% of their excess body weight over 1 year. No patient lost less than 25%, and, within a year of the surgery, mean BMI had decreased from 44.8 to 32.5 kg/m².

Flickinger and associates (1984) examined 210 subjects who received roux-en-y gastric bypass.^[56] The mean weight loss was 51 kg in 18 months, which was then maintained over 36 months of follow-up. Only 4% required a repeat operation.

Sugerman and colleagues (1992) reported that, among patients undergoing gastric bypass, two thirds of their excess body weight was lost over 2 years, 60% of the excess body weight lost was maintained, and more than 50% of excess body weight lost was maintained at 9-years follow-up.^[57]

Roux-en-y and other gastric-bypass procedures generally result in more weight loss than gastric-restriction procedures. When 329 subjects receiving vertical gastroplasty procedures were compared with 623 subjects undergoing roux-en-Y gastric bypass, weight loss was maintained in 47% and 62%, respectively, over 5-9 years of follow-up.^[57]

Other adjunctive procedures that may be performed but that have an unclear utility include visceral fat removal, omentectomy, subcutaneous fat panniculectomy, and large-volume subcutaneous fat liposuction. Klein and colleagues (2004) indicated that liposuction in itself has no utility in improving cardiac risk factor among subjects with obesity.^[58]

Previous procedures, such as jaw wiring, insertions of gastric balloon, and insertions of gastric wrap are no longer popular because of their poor results compared with those newer procedures and because of their high complication rates.

Vagotomy has declined in popularity. On its own, vagotomy is associated with some weight loss, but the weight is typically regained within a few years. A few reports suggest that, when vagotomy is performed with gastric bypass, it increases weight loss by as much as 20%, but this finding has not been consistently replicable.

Among the major procedure-specific postoperative complications to watch for are wound dehiscence, stomal strictures, erosions or ulcers, postprocedure diarrhea, malabsorption, dumping syndrome, and anastomotic leaks with a potential for mediastinitis or peritonitis. In addition, gastric-specific operations can be associated with persistent vomiting, metabolic alkalosis, thiamine deficiency, and malabsorption of iron and vitamin B-12. These operations are more commonly associated with weight-loss failure and inadvertent splenectomy than other methods.

Prevalences for adverse events are approximately 70% for dumping, 50% for dairy intolerance, 40% for constipation and headaches, 15% for depression, and 33% for hair loss. Vitamin B-12 deficiency was found in 25% of patients; incisional hernias, anemia, diarrhea, or abdominal pain, in 15% each; and arrhythmias or single or multiple vitamin deficiencies not involving vitamin B-12, in 10% each.

The mortality rate associated with standard bariatric surgical procedures in an experienced center should not exceed 1.5-2%. The surgical mortality rate is less than 0.5% at centers specializing in bariatric surgery. Mortality rates exceeding this rate suggest a risk-to-benefit ratio that probably is unacceptable.

Subjects who receive bypass procedures are particularly prone to micronutrient deficiency states, especially of calcium, vitamin B-12, folate, and iron.

Among the major specific complications associated with malabsorptive operations are uncontrolled diarrhea, steatorrhea, malabsorption of fat-soluble vitamins, potassium and/or magnesium deficiency, blind-loop syndrome (which includes enteritis, arthropathy, and liver cirrhosis), gallstone development, urolithiasis, and metabolic encephalopathy.

If failure is defined as an inability to ameliorate comorbidities or prevent recurrence of such comorbidities, gastric bypass appears to have a failure rate of approximately 20%. Failure rates based on weight loss are controversial. The overall failure rates for malabsorptive procedures are relatively low, though the need for reversal of the surgery because of resulting adverse effects appears to be relatively high.

Despite the morbidity and mortality risk associated with bariatric surgery, the few reports on the follow-up of subjects undergoing these procedures suggest overall improvement in quality of life. Even more convincing than this finding is that most subjects who undergo these procedures, irrespective of their postoperative complications and difficulties, indicate that they would undergo the procedures again if necessary.

Emerging data suggest that gastric pacing achieved by using implantable electrodes may have substantial significant weight-loss effects. This outcome was initially discovered with the use of gastric pacemaker–devices for gastroparesis in subjects with diabetes.

Transneuronix conducted the first set of trials of a device, and findings were largely reported in abstracts. Medtronic, an established company in the arena of medical devices that developed continuous, subcutaneous insulin-pump technology, acquired Transneuronix, as seen in the image below. Recruitment is ongoing for the Appetite Suppression Induced by Stimulation Trial (ASSIST) to evaluate this technology in patients with obesity and type 2 diabetes.

Gastric electrical-stimulation device.
Cigaina (2002) reported that 10 patients in whom the pacing device was laparoscopically implanted showed a mean excess weight loss of about 25% at 3-year follow-up.^[59]

Similar findings were replicated in several European studies with a total cohort of about 50 patients.

Next Section: Diet

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Next Section: Diet

Consultations

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  Psychiatrist: Consultation with a psychiatrist is vital for identifying persons with psychiatric disorders and personality disorders such as depression, mania, and obsessive disorders that may be worsened by attempts at weight loss if not adequately treated and controlled.
  
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  Dietitians
  
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  Exercise and physical therapists
  
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  Behavioral scientists and/or psychologists
  
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  Bariatric surgeon, in appropriate setting
  

Next Section: Diet

See Medical Care.

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Next Section: Diet

See Medical Care.

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Medication Summary

Few medications are available for the management of obesity. The list of putative therapeutic agents being investigated has increased considerably with the explosion in our knowledge of the pathogenesis of obesity. Improved understanding of the neurocircuitry of the feeding-satiety cycle has provided many potential targets for designer therapeutic agents that are being developed (see image below).

Most medications available for managing obesity are approved only for short-term use. Available literature indicates that their utility is severely limited when they are given in this fashion. Obesity is a chronic medical condition. As with similar chronic conditions (eg, diabetes, hypertension), after therapeutic agents are stopped, the relapse rate is high. The need for any pharmaceutical regimen to be combined with a sustained exercise, dietary adjustment, and a behavioral-change regimen to sustain weight loss further complicates the successful management of obesity.

The only FDA-approved medication for long-term management of obesity in adults and adolescents is orlistat. Adolescents represent the next wave of the obesity pandemic that is anticipated in the next few decades.

A Japanese study found evidence that beverages containing high amounts of catechin, a flavonoid found in green tea, may aid in preventing obesity.^[60] Patients in the investigation, all of whom had type 2 diabetes mellitus, ingested either 582.8 mg or 96.3 mg of catechins per day, by drinking green tea. By the 12th week, participants receiving the higher catechin dose had undergone a significantly greater reduction in waist circumference than did patients receiving the lower dose.

Next Section: Anorexiants

Anorexiants

Class Summary

Anorexiants are administered to manage obesity. Indications included weight loss and maintenance of weight loss, in conjunction with a reduced calorie diet, specifically in patients who are obese with an initial BMI of 30 or 27 mg/m² and other risk factors (eg, diabetes mellitus, dyslipidemia, hypertension).

GI lipase inhibitor that induces weight loss by inhibiting nutrient absorption. Effectiveness in producing weight loss does not depend on systemic absorption. May reduce absorption of some fat-soluble vitamins (A, D, E, K) and beta-carotene. Administer multivitamin supplement containing fat-soluble vitamins PO qd 2 h ac or 1 h pc.

Next Section: Anorexiants

Stimulants release tissue stores of epinephrine, causing subsequent alpha- and/or beta-adrenergic stimulation, have provided benefits to patients with obesity. Approved in adults for short-term use (8-12 wk).

Natural xanthine derivative that directly stimulates all levels of CNS, cardiovascular system, and voluntary muscles. Increases gastric acid secretion and renal blood flow. Has mild diuretic activity.

Sympathomimetic amine that increases release and reuptake of norepinephrine and dopamine. Anorexiant effect occurs as result of satiety-center stimulation in hypothalamic and limbic areas of brain. Pharmacologic component of comprehensive weight-reduction program (including behavioral modification, caloric restriction, exercise) intended for patients with initial BMI 30 or 27 kg/m² and other risk factors (eg, diabetes, hyperlipidemia, hypertension).

Sympathomimetic amine effective as adjunct anoretic therapy of exogenous obesity. Anorexiant effect occurs as a result of satiety-center stimulation in hypothalamic and limbic areas of brain. Controlled substance with high potential for abuse and addiction.

Although weight-management programs may be based in an outpatient or inpatient setting, no rigorous evidence suggests that inpatient programs are necessarily superior to outpatient programs of similar structure and content.

Inpatient programs may offer the convenience of easy access to patients and ease of monitoring, but they are expensive to run, difficult to reimburse, and generally considerably disrupt the patients' regular routine. In addition, they offer little guarantee of sustained effect.

The major role for inpatient evaluations is in the immediate postoperative period after antiobesity surgery and in the management of major complications, such as clinically significant respiratory or cardiac compromise.

Next Section: Further Outpatient Care

Further Outpatient Care

As with the management of other chronic medical conditions that are not presently curable (eg, diabetes mellitus, hypertension, bronchial asthma), long-term success in the management of obesity is contingent on long-standing follow-up with the program.

Visits may not need to occur as frequently during follow-up as during the initial weight-loss phase, but they are paramount if the lessons learned regarding diet, exercise habits, and behavioral patterns are to be maintained.

Experience from the lifestyle intervention group of subjects in the Diabetes Prevention Program and the ongoing Diabetes Prevention Program Observation study have borne out the importance of regular follow-up.

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Because of the sheer prevalence of obesity and the anticipated worsening of the pandemic in the next few decades, prevention is by far the most desirable means to curb the consequences and economic load of obesity. However, few trials have addressed this issue, and those performed thus far have had mixed results.

Results of some public health education initiatives in Singapore and parts of China that are only now being evaluated suggest, as hoped, that such programs have the potential for reducing the incidence and prevalence of obesity and the major comorbidities of obesity, such as type 2 diabetes and hypertension.

Until recombinant DNA methods are developed enough to enable the alteration of genes that predispose individuals to obesity, the only options available are to develop a massive public health education program aimed at both adults and children to change their eating, activity, and behavioral habits.

The potential for possible leptin sensitizers may assist in changing feeding habits.

Given the global proportions of obesity, a concerted approach is needed and should involve cooperative efforts among public health authorities, caterers, the fast food industry, and organizers of sports and outdoor games.

In 2010, the American Heart Association-American Stroke Association (AHA-ASA) issued guidelines for the primary prevention of stroke, with the following recommendations:^[61]

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  Diet and nutrition: A diet that is low in sodium and high in potassium is recommended to reduce blood pressure. Diets that promote the consumption of fruits, vegetables, and low-fat dairy products such as the DASH-style diet help lower blood pressure and may lower risk of stroke.
  
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  Physical inactivity: Increasing physical activity is associated with a reduction in the risk of stroke. The goal is to engage in at least 30 minutes of moderate intensity activity on a daily basis.
  
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  Obesity and body fat distribution: Weight reduction among overweight and obese persons, is recommended to reduce blood pressure and risk of stroke.
  

Next Section: Further Outpatient Care

The potential complications and associations of obesity are detailed in the image below.

Comorbidities of obesity.

The so-called Pickwickian syndrome named after the boy who was obese in Charles Dickens’ Pickwick Papers is a combined syndrome of obesity-related hypoventilation (related to the severe mechanical respiratory limitations to chest excursion from severe obesity) and sleep apnea (which may be from obstructive, central, or both mechanisms).

Apart from the metabolic complications associated with obesity, a paradigm of increased intra-abdominal pressure has been recognized. This pressure effect is most apparent in the setting of marked obesity (BMI ≤50) and is espoused by bariatric surgeons, including Sugerman and colleagues (1992).^[57]

Given findings from bariatric surgery and animal models, this change in pressure may play a (potentially major) role in the pathogenesis of comorbidities of obesity, such as pseudotumor cerebri, lower-limb stasis, ulcers, dermatitis, thrombophlebitis, reflux esophagitis, abdominal hernias, and possibly hypertension and nephrotic syndrome.

Some reports, including those by Adelman and colleagues and Kasiske and Jennette, suggest an association between severe obesity and focal glomerulosclerosis.^{[62, 63, 64]} These complications, in particular, improve substantially or resolve early after bariatric surgery, well before clinically significant weight loss is achieved.

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The association between obesity and morbidity is not in doubt.

However, the previous notion that the increased mortality and morbidity in patients who are obese was not entirely due to comorbidities was controversial.

Results of several observational studies detailed by the Expert Panel on the Identification, Evaluation, and Treatment of Overweight Adults and results from other reports by Allison, Bray, and others exhaustively show that obesity, on its own, is associated with increased cardiovascular morbidity and mortality and increased all-cause mortality.

For a person with a BMI of 25-28.9 kg/m², the relative risk for coronary heart disease is 1.72. This risk progressively increases with an increasing BMI. Therefore, with BMIs greater than 33 kg/m², the relative risk is 3.44.

Similar trends were demonstrated in the relationship between obesity and stroke or congestive heart failure.

Overall, obesity is estimated to increase the cardiovascular mortality rate 4-fold and the cancer-related mortality rate 2-fold.^[20]

As a group, people who are severely obese have a 6- to 12-fold increase in the all-cause mortality rate.

A longitudinal study by Stessman et al of more than 1000 individuals indicated that a normal BMI, rather than obesity, is associated with a higher mortality rate in elderly people. The investigators determined that a unit increase in BMI in female members of the cohort could be linked to hazard ratios (HRs) of 0.94 at age 70 years, 0.95 at age 78 years, and 0.91 at age 85 years. In men, a unit increase in BMI was associated with HRs of 0.99 at age 70 years, 0.94 at age 78 years, and 0.91 at age 85 years. According to a time-dependent analysis of 450 cohort members followed from age 70 to age 88 years, a unit increase in BMI produced an HR of 0.93 in women and in men.^[65]

Similar results to those in the Stessman study were found in a Japanese investigation of 26,747 older persons (aged 65-79 years at baseline). Tamakoshi et al found no elevation in all-cause mortality risk in overweight (measured as BMI 25.0-29.9 in this study) or obese (BMI ≥ 30.0) males; slightly elevated hazard ratios were found in women in the obese group, but not in the overweight group, in comparison with women in the mid – normal-range group. In contrast, an association was found between a low BMI and an increased risk of all-cause mortality, even among persons in the lower-normal BMI range.^[66]

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In studies among low-income families, both adults and adolescents noted caloric information when reading labels.^[67] However, it did not affect food selection by adolescents or the parental food selections for their children. It appears that the caloric content and distribution did not impact decision-making.