A report issued last year by HHS' Agency for Healthcare Research and Quality (AHRQ) concludes that surgery for extremely obese patients who have tried and failed to lose weight with exercise and diet may be more effective for weight reduction. It can also improve control of some obesity-related health problems such as high blood pressure and diabetes. In addition, extremely obese persons—those who have a Body Mass Index (BMI) of 40 or greater—often suffer from severe health problems such as heart disease, musculoskeletal disorders, and sleep apnea that limit daily activities and put their lives at greater risk.

BMI can be calculated as weight in pounds divided by inches squared and then multiplied by 703. An online BMI calculator can be found at www.nhlbisupport.com/bmi/.

.A person who is 5 feet 8 inches tall and weighs 276 pounds has a BMI of 42, for example, and is considered extremely obese.

Roughly 60 million adults in the United States are obese, and 9 million are extremely obese. A BMI of 40 or greater is not the sole criterion for selecting patients who might benefit from weight-loss surgery. Of the 9 million extremely obese adults, only a small fraction, about 1.5 percent or 140,000, undergo weight-loss surgery each year in the United States.

Approximately 20 percent of those who have weight-loss surgery experience complications; although most are minor, some can be serious, according to the study authors. These include nutritional deficiencies, leaks from staple line breakdown, and deep vein thrombosis. Laparoscopic procedures result in fewer wound complications and incision hernias than traditional abdominal surgery.

"Good nutrition and exercise are key elements of a healthy lifestyle and for achieving a healthy weight," said AHRQ Director Carolyn M. Clancy, M.D. "For adults whose health is severely compromised, using surgery to achieve weight loss is an option, but is not a total solution or magic bullet for obesity. Healthy behaviors have an important role in the management of obesity, even for those who have surgery."

The scientific evidence review that was used as the basis for the new AHRQ report found data suggesting that weight-loss surgery, also known as bariatric surgery, may be more effective than drugs for people with BMIs of 35 to 40; however, the evidence is not strong enough to draw firm conclusions for this group.

In addition, the review found that Roux-en-Y gastric bypass surgery results in greater weight loss—an average of 20 pounds—than does vertical-banded gastroplasty.

The AHRQ review did not find enough evidence to draw conclusions about differences in the safety of different types of weight-loss surgery, which include adjustable gastric banding, vertical-banded gastroplasty, and biliopancreatic diversion procedures. Less than than 1 percent of patients operated on by experienced bariatric surgeons die as a result of the surgery or from complications, but the rate may be higher for less-experienced surgeons.

The evidence review also found that some prescription medicines—particularly orlistat and sibutramine, the most widely studied drugs—promote moderate weight loss when prescribed along with recommendations for dieting. The amount of weight loss directly attributable to these drugs averages less than 11 pounds, but research shows that even such a modest weight loss may decrease the occurrence of diabetes.

No weight-loss drug appears to be superior to others, and, like all medications, each has side effects. The drugs have not been studied sufficiently to evaluate the risk of rare side effects, nor has there been enough research to determine the optimal time to treat obesity with drugs or how this may vary by patients' age, gender, or race.

The evidence review found that very little research has been done on either surgery or medical treatment of obesity in children and adolescents.

The report will be considered along with other information when the Medicare Coverage Advisory Committee meets on November 4, 2004, to discuss the risks and benefits of bariatric surgery in the Medicare population.

In December 2003, the U.S. Preventive Services Task Force recommended that clinicians screen all adult patients for obesity and offer or refer obese patients for intensive counseling and behavioral interventions to promote sustained weight loss. The Task Force, which is supported by AHRQ, is the leading independent panel of private-sector experts in prevention and primary care and conducts rigorous, impartial assessments of the scientific evidence for a broad range of preventive services