For Very Obese, Gastric Bypass May Extend Life
MONDAY Jan. 18, 2010 -- Gastric bypass surgery could have life-extending benefits for most of the five percent of Americans who are very obese, a new study suggests.
The study, led by researchers at the University of Cincinnati, concluded that the benefits of this form of weight-loss surgery far outweigh the risks for most people who are morbidly obese, which is defined as having a body mass index of 40 or higher.
But individual decisions on the surgery rely on factors such as age, and a special program to help physicians and obese people balance the benefits and risks of weight-loss surgery is on the way, the researchers said.
"In the future, we plan on having a Web-based decision support tool," said Dr. Daniel P. Schauer, assistant professor of internal medicine at the University of Cincinnati Academic Health Center. "Hopefully, it will be available some time in the next year. It is in the development and testing phase."
The program is based on a study reported by Schauer and his colleagues in the January issue of Archives of Surgery. They examined data on more than 23,000 people who underwent bariatric surgery. The study compared that data to the immediate risk of death from the procedure and the years of life expectancy added by having the surgery.
Obesity is a major risk factor for heart attack, stroke and other cardiovascular problems. An increasing number of Americans who cannot control their weight by diet or behavioral changes have turned to bariatric surgery. Gastric bypass is one of several forms of bariatric surgery, which work by either preventing food from entering the stomach or diverting it past the stomach, thereby reducing food intake and absorption.
Current data indicate that a 42-year-old woman with a BMI of 45 would gain three years of life expectancy through gastric bypass, while a 44-year-old man with the same BMI would gain 2.6 years of life, according to the study. For reference, a 5-foot-9-inch man or woman weighing 305 pounds has a BMI of 45.
The 30-day mortality from the surgery has ranged from almost zero to as high as 2 percent in some studies, but it can be higher for some selected populations, the report said.
"The patients who benefit the most are younger patients who have a lower risk of dying from the surgery and a higher BMI," Schauer said. "The patients who benefit the least are older patients with a higher surgical risk because of a combination of age and comorbidities [other illnesses]."
Their model does not calculate the risk added by specific comorbidities, such as coronary disease, he said. "We are working on that for the next generation of models," Schauer said.
The most recent data used comes from 2007, and there is also reason to believe that the surgical risk has decreased since then, Schauer said. "That is something we are working on, updating the model as it becomes available," he said.
Dr. T. Karl Byrne, professor of surgery and director of bariatric surgery at the Medical University of South Carolina, said he would like to see more information on the cost benefits and health improvements associated with gastric bypass.
Every diabetic costs the health care system $13,000 a year, Byrne said. If you are diabetic and have bariatric surgery, in six months your diabetes goes away. So there is more to it than just life years obtained. There is a huge cost issue that is not addressed in these studies, and bariatric surgery should cost the health care system less in the long term, he said.
A second report in the same issue of the journal reported a marked change in the sites doing bariatric surgery after the federal government approved Medicare and Medicaid payment for the procedure in February 2006.
That coverage required that surgery be done at a medical center certified by the American College of Surgeons or the American Society for Metabolic and Bariatric Surgery. For approval, a center must perform at least 125 operations a year.
The study by physicians at the University of California at Irvine compared results of almost 3,200 operations done just before approval and almost 3,100 done just after approval. It found that the number of facilities doing such surgery decreased from 60 to 45, indicating a shift to certified, high-volume centers.
People who had surgery after approval had shorter hospital stays (3.5 days vs. 3.1 days) and lower rates of complications (12.2 percent vs. 10 percent). No significant difference was seen in the in-hospital mortality rate (0.28 percent vs. 0.2 percent).
"Although we only examined the Medicare beneficiaries population in this survey, we suspect that the improvement in outcomes will also be extrapolated to the population that is not eligible for Medicare," the researchers wrote.
Bariatric surgeries have increased steadily in the United States -- from 16,800 in 1992 to about 205,000 in 2007, according to the American Society for Metabolic and Bariatric Surgery.
For a detailed description of bariatric surgery, see the U.S. National Library of Medicine.
Posted: January 2010