Medical and Surgical Treatment of Obesity

Division of Endocrinology and Metabolism, Inha University Hospital, Incheon

Yong Seong Kim, M.D.

INTRODUCTION

A stepped model for clinical management can be used as the basis for setting guidelines. It confirms to the stepped process of many different types of clinical intervention.

Realistic weight-loss goals, ranging from what would be considered good progress to what would be considered excellent progress. The medium- and long-term goals may not reflect patients’ expectations based on their early losses. But only long-term losses (after one to five years) should be regarded as indicating a successful weight-loss program.

PHARMACOTHERAPY

Pharmaceutical agents used to treat obesity by decreasing energy intake or decreasing energy expenditure, or both. Any drug used to treat obesity should 1) reduce weight,  2)  have no addictive properties, 3) effect outweigh the hazards, 4) be able to be used long term.  And pharmacotherapy can be a useful adjunct to lifestyle change to induce weight loss in some patients with a BMI greater than 30 and in patients with a BMI greater than 27 with co-morbidities.

Research into new anti-obesity drugs is moving quickly, and recommendations may

need to be updated. The four medications currently available, orlistat, sibutramine, phentermine, and diethylpropion. Former two drugs appear to be effective for continued weight loss, although phentermine and diethylpropion are indicated only for shortterm use. Because there is no long-term (over two years) information published in the peer-reviewed literature on the potential harmful effects of these medications,  it is incumbent on the practitioner to prescribe with caution.

Evidence-based statements Evidence level

The dopaminergic agents phentermine and diethylpropion can produce effective weight losses of 6 to 7 kilograms (3 to 3.6kilogram more than placebo), but are currently indicated only for short-term use. Some SSRI (selective serotonin re-uptake inhibitor)

antidepressant medications can result in weight loss in some people under well-controlled conditions, although the effect may be transient despite continued use of drugs.

Sibutramine can lead to a weight loss of 5.6 kilograms or about  6 per cent (4.3 kilogram more placebo), and improve some co-morbid factors after one to two years of treatment. If it is preceded by, or combined with, lifestyle and dietary modifications, weight loss in some individuals can almost double, to 10.8 kilograms, ranging from 5 to 17 kilograms (4 to 5 kilogram above placebo), or about 10.7 per cent. The safety of prolonged (more than two years) therapeutic use of sibutramine has, however, not been demonstrated. The medication should be used with caution in patients with a history of hypertension, and its use is not recommended in patients with coronary artery disease, arrhythmias, congestive heart failure, or stroke.

Orlistat combined with a low-energy, low-fat diet can lead to a weight loss of 8.4 kilograms ranging from 6 to 13kilograms (1.1 to 4.5 kilogram above placebo), or about 8.6 per cent, and improve some co-morbid factors after one to two years of treatment. Two-thirds of this weight loss is the result of diet modification. A recently completed study published in abstract format Level of evidence has shown efficacy and safety in patients over a four-year yet to be assigned treatment period. Both sibutramine and orlistat can increase the likelihood of long-term maintenance of weight loss while the drug is being taken.

SURGERY

Surgical treatment of obesity -bariatric surgery- is designed to produce reduced energy intake, various degrees of malabsorption of nutrients, or both. It is the most

effective treatment for severe obesity currently available, but physicians should

be aware of the following provisos issued by the US National Institutes of Health

Consensus Development Conference Panel.

In general, surgery is indicated for patients with a BMI greater than 40 or with a BMI greater than 35 and serious medical co-morbidities,  although it is increasingly being used in patients with BMIs lower than this.

In a recent meta-analysis, surgery has been shown to cause a mean reduction in BMI

of 16.4kg/m2 at one year, with reductions maintained at 13.3kg/m2 in studies with a

follow-up period of between nine months and seven years.  Therefore, in contrast to

conventional treatment, surgical intervention in severely obese patients can produce

large weight losses that are sustained over time.  Surgical procedures in motivated, morbidly obese patients can result in weight losses of from 16 to 43 per cent (varying between 22 and 63 kilograms) that are reasonably well maintained over three to eight years.

Four procedures have produced the best results to date: Roux-en-Y gastric bypass;

vertical banded gastroplasty (gastric banding); adjustable gastric banding performed

laparoscopically; and biliopancreatic diversion. Laparoscopic gastric banding banding is now by far the most widely used technique making up around 95 per cent of all procedures. It has also been the subject of much recent investigation. Gastric bypass, vertical banding and biliopancreatic diversion are done less often, except perhaps in the US. All four techniques induce impressive weight loss and a clear-cut reduction in many obesity-related co-morbidities. The jejunoileostomy was often used to treat morbidly obese patients between 1970 and 1980, but it has been abandoned because negative consequences and complications were common and reoperation was often necessary.

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Surgically induced weight loss results in a marked reduction in the incidence and severity of some of the co-morbidities associated with obesity (particularly diabetes) and improved quality of life. Obesity surgery may prove cost-effective in morbidly obese patients after two years. In patients with acceptable operative risks, mortality as a consequence of bariatric surgery is low. Bariatric surgery is, however, often associated with impaired absorption of micronutrients, which requires lifelong monitoring and often folate or vitamin B supplementation.

Success after surgery is often defined as a BMI less than 35 because mortality risk

increases rapidly above this degree of obesity.  In other studies success has been

defined as a loss of more than 50 per cent of excess weight.

SUMMARY

Weight-loss drugs should be used only as part of a comprehensive weight-loss

program for people with a BMI greater than 30 or for people with a BMI greater than

27 and with co-morbid risk factors.

Surgical intervention combined with permanent lifestyle change is the most effective

therapy for weight reduction in terms of the extent and duration of weight loss.

Although it is expensive, bariatric surgery also appears to be cost-effective in the

long term. As a result, for morbidly obese individuals with serious co-morbid

conditions and in whom other therapeutic approaches have failed, surgical treatment

is increasingly recognised as the treatment of choice.

REFERENCE

Clinical Practice Guidelines for the Management  of Overweight and Obesity in Adults. National Health and Medical Research Council (NHMRC)

Endorsed 18 September 2003

Website: www.obesityguidelines.gov.au