Jan. 3, 2012 -- Weight loss surgery lowers the risk of having a heart attack or stroke, and the risk of death from these and other heart-related causes, in people who are obese, according to new research in the Journal of the American Medical Association.
The findings come from an ongoing Swedish study comparing long-term outcomes among obese patients who did and did not have the surgery.
Over an average of 14 years of follow-up, the bariatric surgery patients lost much more weight and had fewer heart attacks and strokes than people who did not have the surgery.
They were also almost half as likely to die of heart attacks and strokes.
Weight Loss Surgery and the Heart
But weight loss alone did not appear to explain the difference in outcomes among the two groups, and a patient’s pre-surgery weight -- as measured by body mass index (BMI) -- did not predict the amount of heart health benefit obtained from the bariatric surgery.
Bariatric surgery was associated with about a 30% reduction in the incidence of both heart attacks and strokes, says researcher Lars Sjostrom, MD, PhD, of Sweden’s University of Gothenburg.
While pre-surgery BMI did not predict surgical health outcomes, having diabetes or risk factors for diabetes was a strong indicator of surgical benefit.
200,000 Surgeries Annually in U.S.
About 200,000 weight loss surgeries are performed each year in the U.S., a tenfold increase since the mid-1990s.
Bariatric surgery has been shown to be very effective for achieving weight loss and for treating type 2 diabetes, but its impact on heart attack and stroke risks has not been widely studied.
The Swedish Obese Subjects (SOS) study includes around 2,000 bariatric surgery patients and a similar number of obese people who did not have the surgery.
Most were in their 40s and 50s when recruited for the study between 1987 and 2001, and all were followed until the end of 2009.
Not surprisingly, patients who had the surgery lost much more weight than those who did not.
The average surgery patient had lost 23% of their body weight two years after the procedure and 16% after 15 years, compared to 0% and 1%, respectively, among the non-surgery group.
Ultimately, bariatric surgery was associated with a 53% reduction in deaths from heart attack and stroke and a 33% lower incidence of these events.
'Belly Fat Better Death Predictor Than BMI'
The finding that having diabetes risk factors such as high blood sugar were a better predictor of surgical benefit than BMI could have implications for selecting candidates for weight loss surgery, Sjostrom and colleagues conclude.
Weight loss surgery researcher Edward H. Livingston, MD, of the University of Texas Southwestern Medical Center in Dallas, agrees.
In an editorial published with the study, Livingston writes that obesity alone may not be associated with reduced life span in some people, especially those who don’t carry extra body fat in their belly area.
Body fat that accumulates around the midsection, especially around the area's organs, is a serious risk factor for heart attack and stroke.
“We know that weight loss is a very good treatment for most forms of diabetes,” he tells WebMD. “I think we should be focusing on diabetes and not BMI when we consider who should have this surgery.”
Bariatric surgeon Mitchell Roslin, MD, agrees that BMI alone is a poor predictor of outcomes from weight loss surgery. But he says the main message from the new research is that the surgery prevents heart attack and stroke deaths in many patients.
Roslin is chief of obesity surgery at Lenox Hill Hospital in New York City.
“Heart attack and stroke are major killers of obese people,” he tells WebMD. “This study proves this surgery saves the lives of obese patients with a high risk for heart disease.”