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Studies Weigh Risks of Gastric Bypass Surgery

Long-Term Benefits of Gastric Bypass Surgery Seem to Outweigh Short-term Risks

From the WebMD Archives

Oct. 7, 2004 -- The immediate risks associated with gastric bypass surgery to treat obesity may be much higher than previously thought. But the long-term benefits of gastric bypass surgery in preventing death will likely outweigh those risks, according to new research.

Two new studies highlight the risks and benefits of increasingly popular bariatic or obesity-related surgeries, such as gastric bypass surgery, to treat people who are at extremely obese or morbidly obese in medical terms.

The first study shows that the risk of death within 30 days after gastric bypass surgery is at least four times higher than previously reported, and much of that risk was attributable to the surgeon's inexperience.

"It turns out that the 1 in 500 or 1 in 200 risk of death that people are commonly quoted comes from the best surgeons," says researcher David R. Flum, MD, MPH, assistant professor of surgery at the University of Washington. "In fact, in the real world ...the risk of dying within 30 days of surgery is about one in 50."

But Flum's study also showed that the long-term risk of death was much lower among those who had gastric bypass surgery compared with obese persons who did not.

Those long-term benefits in reducing the risk of death were echoed by the second study, which showed that morbidly obese people who had gastric bypass surgery had an 89% lower risk of death in the next five years compared with morbidly obese people who did not.

Experts say the studies show that gastric bypass surgery is not without risks, but those risks may be worth it over the long run.

"It's clear that bariatric surgery is the most effective therapy we have for people who have extreme obesity," says Samuel Klein, MD, council member of the North American Association for the Study of Obesity." It is also most costly in financial costs and mortality, but the benefits clearly outweigh the risks for properly selected patients."

Weighing the Risks of Gastric Bypass Surgery

During a gastric bypass surgery, surgeons create a small pouch in the stomach with staples or a plastic band, which dramatically reduces the amount of food a person can eat. In addition, a portion of the small intestine is attached to the pouch to allow the food to bypass the rest of the stomach and the upper portion of the small intestine in order to reduce calorie and nutrient absorption.

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This procedure can be done by making a large incision in the abdomen or by making several small incisions and using small instruments and a camera to guide the surgery, which is known as laparoscopic surgery.

The popularity of gastric bypass surgery in the U.S. for the treatment of obesity has surged in recent years with a more than 10-fold increase in the number of procedures performed in 2001 compared with 1987. This increase has been attributed to both the rise in obesity rates and the availability of less invasive laparoscopic techniques.

In fact, Flum's study showed the number of gastric bypass surgeries performed among the patients studied increased by 250% after laparoscopic gastric bypass surgery was introduced in 1997.

Although the procedure has become increasingly common, Flum says his study is the first to look at the effect of gastric bypass surgery on the risk of death in the "real world" among a large number of people who had the procedure performed by a variety of surgeons. The results appear in the November issue of the Journal of the American College of Surgeons.

The study compared the number of deaths following gastric bypass surgery in more than 3,300 obese people who had the procedure from 1987 to 2001 with those reported among a group of more than 60,000 similarly matched obese people who did not have the procedure.

Researchers found the short-term risk of death following gastric bypass surgery was much higher than previously thought, specifically:

  • 1.9% of gastric bypass surgery patients died within 30 days after the procedure, which is four times higher than the rate of about 0.5% suggested by smaller previous studies.
  • Nearly half of all early deaths occurred after the patient came home from the hospital.
  • The risk of death within 30 days after gastric bypass surgery was nearly five times higher if the surgeon had performed less than 20 of the procedures than if the surgeon had more experience.
  • Of the cases in which the patient died within 30 days after gastric bypass surgery, 81% were among the surgeons first 19 gastric bypass surgeries.

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Long-Term Benefits of Gastric Bypass Surgery Pay Off

However, the study also showed that obese people who had gastric bypass surgery had a much lower risk of death over the long-term. After 15 years of follow up, 16% of obese people who did not have gastric bypass surgery died compared with 12% of those who did.

The long-term benefits of gastric bypass surgery in reducing the risk of death were greatest among young patients who were under 40 and the morbidly obese. After more than 13 years of follow up, only 3% of those who had the procedure died compared with 14% of morbidly obese people who did not have the procedure.

"The bottom line is that bariatric surgery, specifically gastric bypass, is a complicated operation in a complicated group of people," Flum tells WebMD. "When it's effective, it's very effective, but it has some real risks."

The second study, which appears in the September issue of the Annals of Surgery, also showed that gastric bypass surgery significantly reduced the risk of death over the long-term among morbidly obese people.

Canadian researchers followed more than 5,000 morbidly obese people who did not have surgery and compared them with nearly 1,000 morbidly obese people who had a gastric bypass between 1996 and 2002.

After five years of follow up, the study showed that 0.68% of those who had gastric bypass surgery died compared with 6% of the others, which translates to an 89% reduction in the risk of death.

The study also showed that people who had gastric bypass surgery had lower risks of developing heart disease, cancer, diabetes, and mental disorders compared with those who didn't.

Choose Your Surgeon Wisely

Klein says the results of these studies confirm that gastric bypass surgery is a complicated procedure that comes with a certain degree of risk that should not be taken lightly.

Flum's study shows that there is a learning curve for surgeons who perform gastric bypass surgery. But Klein says once surgeons have gained experience and performed more than 20 procedures, the short-term risk of death is much lower and closer to 0.5%, as reported in previous studies, than the 1.9% found in this study.

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"This is a lesson for people who are considering the operation to really go with a surgeon who has a track record and experience and have it done at centers that have experience with doing the operation," Klein tells WebMD. "There is an initial risk of increased death from the operation, which seems to be much higher in inexperienced surgical hands than experienced surgical hands."

In addition, Klein says reducing the risk of death may not be the most important benefit of gastric bypass surgery. Previous studies have shown that gastric bypass surgery can reduce and prevent obesity-related diseases, such as diabetes and heart disease, and improve the quality of life for people who are morbidly obese.

WebMD Health News

Sources

SOURCES: Flum, D. Journal of the American College of Surgeons, October 2004; vol 199: pp 543-551. Christou, N. Annals of Surgery, September 2004; vol 240: pp 416-424. David R. Flum, MD, MPH, assistant professor, department of surgery and school of public health, University of Washington. Samuel Klein, MD, director, Center for Human Nutrition, Washington University School of Medicine; past president, council member, North American Association for the Study of Obesity. WebMD Medical Reference from Healthwise: "Gastric Bypass."
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