Two large studies have found that bariatric surgery in obese patients is directly associated with improved long-term survival, providing a ‘missing link’ in the chain of evidence between weight loss and reduced mortality.
The first study examined 4,047 obese Swedes, half of whom chose to have one of three open surgical procedures to help them lose weight. Weight loss ten years later averaged from 14% to 25% depending on the procedure used, while controls lost just 2%. There were 29% fewer deaths during follow up among participants who had surgery, after accounting for sex, age and other risk factors.
The second study compared 9,949 Americans who had gastric bypass surgery with a group of similarly obese controls identified from driver’s licence data. During a mean follow-up of seven years, subjects who had surgery had a 40% lower rate of death from any cause. Key components included reductions of 56% in deaths from coronary artery disease, 92% in deaths from diabetes, and 60% in deaths from cancer. However, the rate of death from other causes, including accidents and suicide, was almost doubled.
An editorial noted that weight loss in obese people had been associated with many benefits including a lower incidence of, or easier control of, diabetes, hypertension and dyslipidaemia, as well as better quality of life.
“What has been missing from the equation is a demonstration that improvement in these risk factors translates into longer life,” it said. “The question as to whether intentional weight loss improves life span has been answered, and the answer appears to be a resounding ‘yes.”
The studies were conducted before adjustable laparoscopic gastric banding became widely available. This newer technique had been shown to achieve more sustained weight loss in some patients, and was associated with a more rapid postoperative recovery and less procedure-related mortality. Future death rates from bariatric surgery should therefore be lower, and achieve a greater net benefit.
Reference
Bray, G. 2007. 'The missing link — lose weight, live longer.' New England Journal of Medicine vol. 357, pp. 818-820.
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