Weight loss surgery fails to lower risk of dying in severely obese middle-aged adults: Study

By Dr. Ananya Mandal, MDJun 13 2011

According to a new study, weight loss surgery doesn't decrease the risk of death among severely obese middle-aged adults.

For the study the researchers from the US looked at 850 male patients at Veterans Affairs medical centers who had weight-loss (bariatric) surgery between January 2000 and December 2006. Their average age was 49.5 and their average body mass index was 47.4 (a body mass index – i.e. weight in kg over height in meters squared, or BMI, over 40 is considered severely obese). They compared death rate in this group of patients was compared to that of a control group of about 41,000 VA patients (average age 54.7, average BMI 42) who didn't have surgery.

Results showed that 11 of the 850 bariatric surgery patients (1.29 percent) died within one month after surgery. Unadjusted analysis of the death rates over a six-year period showed that the bariatric surgery patients had lower death rates than those in the control group. In other words when study authors compared the raw rates, patients who had surgery had lower mortality rates with 6.8 percent versus 15.2 percent after six years. But further analysis showed that bariatric surgery was not significantly associated with reduced risk of death, said Matthew L. Maciejewski, of the Durham VA Medical Center in Durham, N.C., and colleagues. Matthew Maciejewski, of Durham VA Medical Center and colleagues concluded that “bariatric surgery does not appear to be associated with survival during a mean of 6.7 years of follow-up.”

“Nearly all prior studies have found bariatric surgery to be associated with reduced mortality. But those studies were conducted on very different patient populations using less rigorous methods,” said lead author Maciejewski.

The study published online and in the June 15 print issue of the Journal of the American Medical Association, was to be presented Sunday at an Academy Health annual research meeting in Seattle.

However in spite of no benefits to mortality rates, there's strong evidence that weight loss surgery reduces body weight and obesity-related health problems, and improves quality of life, the researchers said. For the severely obese, bariatric surgery is one of the most effective ways to reduce weight.  The most common bariatric surgery is gastric bypass, which creates a small stomach pouch that restricts food intake.

“It may be too little too late,” said Dr. Philip Schauer of Cleveland Clinic's Bariatric and Metabolic Institute. He was not involved in the study. “You may have to intervene earlier for a survival benefit.” Evidence has been mounting for the health benefits of obesity surgery, so the new results may surprise some people. U.S. doctors now perform more than 200,000 obesity surgeries a year at an estimated cost of $3 billion to $5 billion. Schauer said a definitive study on survival could cost $200 million.

“These results are not an indictment of surgery,” Maciejewski said. He and his colleagues plan to follow the patients longer to see if a survival benefit shows up 10 to 14 years after surgery.

Dr. Bruce Wolfe, president of the American Society for Metabolic & Bariatric Surgery and a professor of surgery at Oregon Health & Science University in Portland, said the researchers may see a survival benefit with more years of follow up. “This probably won't deter many people who want surgery,” said Wolfe, who wasn't involved in the new study. “They're sick. They have joint disease. They have trouble breathing. They're doing it to improve their health and quality of life.”