A new US study shows that severely obese patients who have gastric bypass surgery have a significantly lower risk of death from cancer, coronary heart disease, and diabetes. However non-disease related deaths are likely to be higher among gastric bypass patients than those who do not have surgery, the researchers concluded.
The study is published in the 23rd August issue of the New England Journal of Medicine and was led by scientists based at the University of Utah School of Medicine and LDS Hospital.
Lead author, Dr Ted D. Adams, professor at the Division of Cardiovascular Genetics in the University of Utah School of Medicine and co-founder of the Intermountain Health and Fitness Institute of LDS Hospital in Salt Lake City, said that:
“This study helps to further define the effects of gastric bypass surgery on long-term mortality.”
“Reduction in death by any cause, and disease-specific deaths such as coronary heart disease, diabetes, and cancer were significantly reduced in surgery patients compared to the non-surgical control group,” he added.
But, he explained that: “rates of death not caused by disease were shown to be greater in those who underwent the weight-loss surgery when compared to controls”.
The research took 14 years and involved 15,850 obese patients, 84 per cent of whom were women. Half of the participants had gastric bypass surgery to reduce weight.
The average BMI (body mass index, weight in kilos divided by the square of the height in metres) of the surgery group was 45.3 and 46.7 for the non surgery group.
The results showed that:
- Deaths due to coronary heart disease were 56 per cent lower in the group that had surgery compared to the non surgery group.
- Deaths due to cancer were 60 per cent lower in the surgery group than the non surgery group.
- Deaths due to diabetes were 92 per cent lower in the surgery group than the non surgery group.
- But, deaths due to other non disease causes such as accidents and suicide were 58 per cent higher in the surgery group than the non surgery group.
The study concluded that:
” Long-term total mortality after gastric bypass surgery was significantly reduced, particularly deaths from diabetes, heart disease, and cancer. However, the rate of death from causes other than disease was higher in the surgery group than in the control group.”
The study suggests that perhaps the non disease caused deaths could be due to mood related or post traumatic stress disorders that existed pre surgery but went undiagnosed. These disorders are said to be more prevalent in obese patients.
Adams said the study showed there was a need to improve the way patients are assessed for surgery and this assessment should include psychological and psychiatric evaluation as well as follow up.
The reduction in deaths associated with disease is highly plausible because after gastric bypass obese patients usually have lower blood pressure, reduced sleep apnea, and also less severe diabetes, and in some cases the diabetes is resolved, explained Adams.
Another study carried out on Swedish patients appears in the same issue of the NEJM with similar results, although the Swedish surgery group also included banding procedures as well as surgical bypasses.
In an accompanying editorial, Dr. George Bray of Louisiana State University suggests that national guidelines for assessing the threshold for gastric bypass and other bariatric surgery should perhaps be re-examined in the light of these results.
However, another bariatric surgery specialist, Dr John Alverdy from the University of Chicago told the city’s Tribune newspaper that it was unlikely things would change very much in the US as a result of these studies.
“Even though the risk-benefit ratio is in favor of the surgery and it is cost-effective, not every insurance company covers it, not every doctor believes in it, and not everyone has access to hospitals that do it,” Alverdy said to the Chicago Tribune.
He said there is a belief that diet and exercise can cure obesity, and that it is the patient’s fault they are obese. This makes patients reticent about seeking surgery and makes some doctors hesitant about recommending it.
This is in spite of the fact research shows that genetics and environment and not just “volition alone” play a role in the development of the disorder, said Alverdy to the newspaper.
“Long-Term Mortality after Gastric Bypass Surgery.”
Adams, Ted D., Gress, Richard E., Smith, Sherman C., Halverson, R. Chad, Simper, Steven C., Rosamond, Wayne D., LaMonte, Michael J., Stroup, Antoinette M., Hunt, Steven C.
N Engl J Med 2007 357: 753-761
Volume 357:753-761; August 23, 2007; Number 8
Written by: Catharine Paddock