SAN FRANCISCO — Bariatric surgery may carry a higher mortality risk than previously reported, according to a study of Medicare patients presented by David R. Flum, M.D., at the annual clinical congress of the American College of Surgeons.
Previous reports have suggested that the mortality risk from gastric bypass procedures is only 1%–2%.
In the new study, Dr. Flum and colleagues looked at a Medicare database of 16,000 gastric bypass procedures performed between 1997 and 2002. Patients in the database were mostly female (75%), and the average age of the patients was 47 years, with 90% younger than 65 years.
The investigators could not tell if the procedures were open or laparoscopic; however, most were presumed to have been open given the time period.
The analysis showed that the mortality rate was 2.0% at 30 days post procedure, 2.8% at 90 days, and 4.6% at 1 year, said Dr. Flum of the surgery department at the University of Washington, Seattle.
Older patients and males had a higher risk of mortality than other patients, a fact that most surgeons who perform obesity procedures are well aware of, he said. The 30-day mortality rate was 3.7% for males versus 1.5% for females, and the mortality risk of patients 65 years or older was 3 times that of patients younger than 65, with a mortality rate of 44% at 1 year among those 75 years or older.
The investigators also calculated patient mortality for the individual surgeons who performed the procedures.
Analysis showed a pattern of lower mortality with the surgeons who performed the highest number of Medicare procedures, although it is not known from the data whether that pattern represents better technical skill or more restrictive patient selection by those experienced surgeons, Dr. Flum said.
Among the surgeons who performed the most procedures (more than 71 during the period studied), the 30-day mortality for patients older than 65 years (1.8%) was about the same as it was for younger patients (1.1%).
Dr. Flum noted that Medicare patients are either over 65 years of age or disabled, and therefore probably do not reflect the general population of patients who undergo bariatric surgery.
Moreover, the study does not indicate what the mortality would have been in this population had they not undergone surgery.
Still, the study provides important information, particularly now with the number of procedures continuing to grow, Dr. Flum said.
“I think trying to make it look like bariatric surgery has zero deaths, which has been an approach used by many advocates for a decade, is problematic,” he said. “This helps set the bar more realistically.”
“If we don't use these data to help start an enlightened conversation about how to apply bariatric surgery, we're really missing a tremendous opportunity,” he added.