Bariatric Surgery: Is It Worth the Risks?

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As the rate of obesity has climbed in the United States over the past few decades, to the point that nearly a third of adults are considered obese, so has the rate at which people are turning to some form of bariatric surgery to help control their weight. These operations are more than cosmetic "tummy tucks" or liposuction. The surgery may involve simply using a band around the stomach or stapling part of it closed to decrease its capacity. More extensive procedures also include bypassing part of the small intestine to decrease nutrient and calorie absorption. Over 100,000 such surgeries were performed in 2003. (1)

While it has been amply demonstrated that bariatric surgery, especially the type that bypasses part of the small intestine, can bring about substantial weight loss and help ameliorate or prevent various obesity-associated ills, it is not known whether such surgery actually prolongs life. Further, the extent to which the health benefits seen in the short term are maintained over many years is not well documented. A study in the December 23 issue of the New England Journal of Medicine begins to address these issues. (2)

Researchers with the Swedish Obesity Study (SOS) compared health indicators of subjects who had undergone some type of bariatric surgery with those of equally obese patients, matched for age, gender, blood pressure, blood cholesterol and triglycerides, and other characteristics. The assignment of patients to the surgery or non-surgery group was not random -- individuals chose whether they wanted to undergo the surgery. Subjects in all groups were decidedly obese, with BMIs of 40 or more (a BMI of 30 is considered obese).

Two years post- surgery, the obese patients who had been operated upon had lost slightly over 23% of their body weight, while the control group had lost only about 0.1% of theirs. At the ten-year follow up, the surgical patients had maintained about a 16% body weight loss, while the non-operated subjects had gained 1.6% of their original body weight.

At both the two- and ten-year follow-up examinations, the surgery group had fewer new cases of both diabetes and hypertriglyceridemia (an elevated blood fatty substance), but there were no differences between the groups in new cases of high blood cholesterol or high blood pressure. The researchers reported that after ten years, individuals in the surgery group also were more physically active and ate less than the controls. In addition, the surgical patients were more likely than the control patients to see improvements in some of the risk factors for heart disease at ten years -- such as diabetes, low levels of HDL ("good") cholesterol, and high blood pressure -- that had been present at the beginning of the study. There were some risks involved, however. Of the 2010 surgical patients, five (0.25%) died post-operatively. Thirteen percent experienced postoperative complications such as bleeding, infections, or blood clots.

Thus, bariatric surgery, while a drastic means of controlling body weight, seems to have health benefits that outlast the short-term postoperative period for such severely obese individuals. Whether or not the reductions in risk factors for cardiac problems seen in the SOS patients will also result in a reduction in cardiac deaths, and whether these results will be replicated, remains to be demonstrated.

(1) Steinbrook R. Surgery for severe obesity. N Eng. J Med. 2004;350:1075-9.
(2) Sjostrom L Lindroos A-K, Peltonen M, et al. Lifestyle, diabetes, and cardiovascular risk factors 10 years after bariatric surgery. N Engl J Med 2004;351:2683-93.

Ruth Kava, Ph.D., R.D., is Director of Nutrition at the American Council on Science and Health.