UW News

October 27, 2005

Gastric bypass surgery grows riskier in senior years

Among patients who are insured by Medicare, the risk of early death after bariatric surgery, sometimes known as gastric bypass surgery, is considerably higher than has been suggested by previous research.

According to an article in the Oct. 19 issue of the Journal of the American Medical Association, death soon after surgery was strongly associated with advancing age. Men and patients of surgeons with less experience in bariatric surgery were at highest risk.

Dr. David Flum, UW associate professor of surgery and director of the Surgical Outcomes Research Center, and colleagues conducted the retrospective cohort study by surveying all Medicare beneficiaries nationwide who underwent bariatric surgery between 1997 and 2002. The objectives of the study were to evaluate the risk of early death among these patients and to determine the relative risk of death among older patients.

“Several case series have demonstrated that bariatric surgery can be performed with a very low rate of post-operative mortality, somewhere under 1 percent,” Flum said. “These reports, though, are often from the best doctors doing surgery in the best circumstances. We wanted to show what the risks are in high-risk patients, such as medically disabled Medicare patients and older Medicare patients, as well as in the community at large. Studying Medicare patients undergoing these operations at nearly every hospital in America gives us more realistic numbers that patients can use in their decision to have this surgery.”

The rates of 30-day, 90-day and one-year mortality from all causes were 2 percent, 2.8 percent and 4.6 percent respectively. Men suffered death rates more than twice those of women. After statistical adjustments for gender and existing medical problems, such as diabetes, osteoarthritis or heart disease, the odds of death were about four times greater for Medicare recipients over 65. Patients who were 65 and older had a 30-day mortality rate of nearly 5 percent. The risk of death at 90 days was 1.6 times higher for patients whose doctors had less experience with this particular type of surgery.

“Our goal for this study was to help inform patients, clinicians, insurers and others involved in medical decision-making about the risk of early post-surgical death in the general community and among higher risk patients,” Flum said. “Although Medicare pays for some of these operations, there is no national insurance coverage decision so far, and no consensus on the efficacy and safety of bariatric surgery in older patients.”

He added, “Most adults in the United States are overweight or obese, and obesity will likely soon become the leading cause of death. For patients with extreme obesity, bariatric surgery is so far the only intervention that consistently helps patients achieve significant and sustained weight loss, but bariatric surgery is not for everyone. This research is helping us to understand which groups of patients are particularly high-risk. Those considering this surgery, particularly older adults, should balance the risk of bad outcomes against the anticipated benefits of the procedure.”