A new publication from the Swedish Obese Subjects (SOS) study found that obese patients who had bariatric surgery were less likely to experience a heart attack or stroke–or die from one—in comparison with patients who were managed without surgery. The study was made-up of just over 4,000 obese patients, treated at 500 surgery departments and health care centers in Sweden. The patients were enrolled from 1987 through 2001, during which roughly half of the participants received bariatric surgery, while the other half (the control group) were treated with routine care, which included advice on healthy lifestyle changes. Of the surgery patients, 13.2 percent underwent a gastric bypass procedure, 18.7 percent had a (non-adjustable) gastric band and 68.1 percent had a vertical banded gastroplasty.
The study found that there were 28 deaths from cardiovascular events in the surgery group and 49 deaths in the control group. Including both fatal and nonfatal cardiovascular events, there were 234 events among patients in the control group and 199 cardiovascular events among patients in the surgery group. An analysis of these figures, including adjusting for variables, indicated that bariatric surgery was associated with a reduced number of fatal cardiovascular deaths and a lower incidence of total cardiovascular events. Specifically, surgery patients were about 30 percent less likely to suffer from a stroke or heart attack than patients in the control group, and half as likely to die from one.
The researchers, however, did not find a significant relationship between degree of weight change and cardiovascular events in the surgery or control group. How much weight patients lost in either group wasn’t tied to their chances of having a heart attack or stroke. One theory is that weight loss surgery has other health benefits that are independent of the degree of weight lost, such as diabetes improvement, which could reduce heart risks. These results show that there are several benefits of bariatric surgery, some of which are independent of the degree of the surgically induced weight loss. However, bariatric surgery, like any surgical procedure, is not without risks and the decision to undergo surgery should be carefully analyzed.
This study was printed in the January 4, 2012 edition of JAMA. An earlier study of the Swedish data found that weight loss surgery had reduced new cases of diabetes by 80 percent among obese patients. You can read more about the earlier findings here.
Weight Loss Studies & Clinical