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Surgical Treatment of Morbid Obesity

National Institutes of Health
Consensus Development Conference Statement
December 4-5, 1978

This statement is more than five years old and is provided solely for historical purposes. Due to the cumulative nature of medical research, new knowledge has inevitably accumulated in this subject area in the time since the statement was initially prepared. Thus some of the material is likely to be out of date, and at worst simply wrong. For reliable, current information on this and other health topics, we recommend consulting the National Institutes of Health's MedlinePlus

This statement was originally published as: Surgical Treatment of Morbid Obesity. NIH Consens Statement 1978 Dec 4-5;1(10):39-41.

For making bibliographic reference to the statement in the electronic form displayed here, it is recommended that the following format be used: Surgical Treatment of Morbid Obesity. NIH Consens Statement Online 1978 Dec 4-5 [cited year month day];1(10):39-41.


On December 4-5, 1978, about 200 surgeons, internists, basic scientists, psychiatrists, psychologists, legal experts, patients and representatives from health insurance companies convened under the sponsorship of the National Institute of Arthritis, Metabolism, and Digestive Diseases of the National Institutes of Health in Bethesda, Maryland, to discuss the current status of surgical treatments or very severe or "morbid obesity." This meeting was one of an ongoing series of consensus development conferences through which the National Institutes of Health seek to establish agreement among knowledgeable experts in the different relevant disciplines concerning the soundness, feasibility, selective applicability and desirability of utilizing various newly developed and emerging medical technologies in clinical treatment and care.

The National Center for Health Statistics of the United States Public Health Service reported that among men aged 20 to 74 years of age in the United States, 4.9 percent or an estimated 2.8 million men were severely obese (30 percent above "relative desirable" weight). The corresponding percentage for women (more than 50 percent above relative desirable weight) was 7.2 percent or an estimated 4.5 million. The "morbid" form of severe obesity has been variably defined as "100 pounds overweight" or, more acceptably, 200 percent or more of desirable weight.

A small survey of currently available information on mortality among morbidly obese persons showed that the death rate among such individuals may range up to eleven times that of nonobese persons of the same age and sex. Severe obesity predisposes to a variety of serious disorders ranging from coronary heart disease, hypertension and diabetes mellitus to marked osteoarthritis of the weight-bearing joints, respiratory distress, gall-bladder disease and psychosocial incapacity (including social and economic discrimination). Although a variety of drastic medical treatments has been tried in the treatment of morbid obesity, including prolonged fasting and very low calorie diets consisting principally of protein, only one to two-thirds of morbidly obese persons will remain on these regimens long enough to lose a substantial proportion (up to two-thirds) of their excess weight. It is estimated that only about 10 to 20 percent of this initially successful group are able to maintain the loss for more than a few years. Thus, it was concluded that for most persons with morbid obesity, current modalities of medical treatment are ineffective. Accordingly, the potential benefits and risks of surgical interventions designed to deal with this problem were thoroughly explored.

The surgical procedures that were intensively reviewed and compared were the jejunoileal bypass and the gastric bypass. Gastroplasty vagotomy, jaw-wiring, and various approaches that are still at an earlier experimental stage were also discussed.

It was generally agreed that, in contrast to the more established jejunoileal bypass, the gastric bypass operation has fewer long-term side effects; however, follow-up has been only two to three years compared to five to seven years for the jejunoileal bypass. Moreover, the gastric bypass operation appears to be a technically more demanding procedure. It is still not known whether patients with gastric bypass will lose as much weight or maintain substantial weight loss for as long a period of time as those receiving intestinal bypass. Gastroplasty, a new variant of gastric bypass, is promising, but assessment of its long-term effect on weight loss is not yet possible. Indeed, the techniques designed to reduce the gastric reservoir are still evolving rapidly.

The most common, serious complications of jejunoileal bypass include a high incidence of oxalate-containing kidney stones, unremitting diarrhea, development of various nutritional deficiencies, and possibly accelerated gallstone formation. Serious kidney problems may also develop. A few patients eventually regain much or all of their lost weight. Other long-term complications include a sometimes fatal liver cirrhosis (probably related to bacterial overgrowth in the excluded intestinal segment). Many of these complications can be prevented or reduced by meticulous follow-up care.

Benefits associated with weight loss, regardless of the procedure used, include frequent amelioration of hypertension, reversal of cardiorespiratory impairment, reduction of hypertriglyceridemia, improvement and sometime disappearance of maturity-onset diabetes, greater physical mobility, and frequently a striking psychosocial rehabilitation. It is also noteworthy that, despite certain distressing complications, a majority of patients who have received the jejunoileal bypass say that they would "do it again."

Consensus was reached that surgical interventions should be limited to morbidly obese patients with serious physical health or psychosocial handicaps who have given suitable nonsurgical treatments a fair trial on repeated occasions and who have failed to show long-term improvement.

For the patient who undergoes a bypass procedure, the outcome is likely to be less predictable than it is for many other, more established operations. Because of these uncertainties, it was agreed that the development and use of a truly informed consent mechanism was essential. It was emphasized that the patient should receive all the relevant information that he would need to make an informed judgment and that such information should be presented in an objective and readily understandable fashion. If both procedures are available, patients should receive a thorough explanation about the risks, benefits and uncertainties of each bypass procedure and be permitted to choose between them.

Comparison of the different surgical procedures was found difficult because of constantly changing surgical techniques and follow-up data of insufficient size and duration, particularly among the more recently developed operations.

Careful follow-up studies of gastric bypass and gastroplasty will be needed to determine whether long-term weight reduction can be maintained in a majority of subjects by means of these procedures. In this regard, it was deemed essential to develop standardized methods for case selection, surgical techniques and follow-up; otherwise, comparative assessment of the different surgical approaches will be difficult, if not impossible. It was agreed that many of the differing results reported for jejunoileal or gastric bypass operations result simply from variations in surgical technique.

Despite the difficulties inherent in evaluating a growing number of different surgical procedures, it was agreed that clinical trials of the most promising new techniques and improvements of existing procedures should be encouraged, so long as they are theoretically well-grounded, tested in animal models, when appropriate, and adhere to carefully thought-out protocols previously approved by a properly constituted institutional review committee.

It was appreciated that a number of important research concerns remain with respect to surgical treatment of morbid obesity. First, a better understanding of the different types of obesity and their implications for health and response to treatment is essential. Next, more data are needed concerning the incidence of massive obesity and the degree of risk associated with such severe obesity. Also required are better techniques to identify early in life those individuals who are destined to become morbidly obese. The mechanism of the effects of the surgical therapies--particularly on the control of food intake--needs much more attention. The ethical issues involved in such surgery, particularly as they can be dealt with by use of properly designed informed consent procedures will require further thoughtful consideration.

It was deemed imperative that bypass operations should only be performed in a setting that provides a multidisciplinary team of highly qualified physicians and surgeons committed to critical case selection, meticulous management, and long-term follow-up.  

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National Institute of Arthritis, Metabolism, and Digestive Diseases

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