Procedure’s Benefits Go Beyond Weight Loss
By RON WINSLOW
About 200,000 Americans undergo surgical procedures to shrink their stomachs each year in the hope that the resulting weight loss will prevent heart attacks and other consequences of obesity.
Now, a new study that tracked more than 4,000 Swedish patients for a median follow-up of nearly 15 years found the procedures were associated with significant relative reductions in risk of heart-related death, heart attacks and strokes.
Those benefits weren’t associated with the degree of weight loss.
The findings support growing evidence that the benefits from the surgery—one of the few effective remedies against extreme obesity—come from a variety of biological changes that often occur independently of weight loss.
“Given the known association between obesity and cardiovascular disease, intuition would have predicted that the reduced incidence of cardiovascular events would be related to weight loss,” write the research team, led by Lars Sjöström of Sweden’s University of Gothenburg. But the researchers failed to find a significant link between the two.
The findings challenge the practice of using a measurement called body mass index, or BMI, as the key criterion for eligibility for the procedure, some researchers say.
The new study found that the absolute benefit in reducing risk of serious heart events was small: There were 28 heart-related deaths over the study period among 2,010 patients who underwent surgery, compared with 49 deaths among 2,037 who were in a matched control group.
Reports from the same patient group, including one published in 2007, found surgery was associated with a reduction in death from any cause, and favorable outcomes for cancer, diabetes and other conditions.
U.S. guidelines say candidates for surgery should have a BMI, a calculation based on height and weight, of 40 or more, or 35 or more with a obesity-related disease such as diabetes. Last year, the U.S. Food and Drug Administration lowered the requirements for a less invasive bariatric strategy called gastric- banding to patients with a BMI between 30 and 40 who have at least one complicating disease.
The new study wasn’t a randomized trial—patients between 37 and 60 years old who underwent one of three different approaches to surgery were matched with patients of a similar gender, age and BMI.
Average weight loss among bariatric patients ranged between 16% and 23% for up to 20 years of follow-up, compared with about zero in the non-surgical patients.
Robin Blackstone, president of the American Society for Metabolic and Bariatric Surgery said recent research shows biological effects of surgery, including lower levels of a hormone called leptin, appear to explain benefits not associated with weight loss.
Write to Ron Winslow at firstname.lastname@example.org