ORLANDO – Bariatric surgery achieved an unprecedented level of safety through 2009, as U.S. surgeons mastered the laparoscopic gastric bypass approach and offered patients gastric banding or gastroplasty, based on data collected on more than 100,000 U.S. patients treated at academic medical centers during 2002-2009.
This recent era also ushered in a new list of risk factors for in-hospital mortality in patients undergoing bariatric surgery, including two modifiable risk factors: diabetes and the type of surgery used, Dr. Brian R. Smith said at the annual meeting of the American Society for Metabolic and Bariatric Surgery.
"We find six preoperative factors that predict mortality. We can’t change patient age, sex, or insurance type, but we can better manage their diabetes preoperatively, and we can change the type of surgery they receive" to minimize their risk, said Dr. Smith, a surgeon at the University of California, Irvine, and chief of general surgery at the Veterans Affairs Healthcare System in Long Beach, Calif.
"Bariatric surgery is now statistically safer than appendectomy. Probably the most significant factor is that [surgeons] have gotten better with the laparoscopic approach; we got over the learning curve," he said in an interview.
Dr. Smith and his associates reviewed 105,287 patients who underwent bariatric surgery during 2002-2009 at hospitals that contribute data to the University HealthSystem Consortium, a database of about 360 U.S. academic medical centers and affiliated hospitals. During that period, bariatric surgery volume ranged from about 10,000 cases in 2002 to about 16,000 in 2009.
Through 2003, open gastric bypass was used exclusively but, starting in 2004, surgeons began performing laparoscopic gastric bypass and gastric banding. By 2005, about 60% of the roughly 13,000 bariatric procedures that year involved laparoscopic bypass, with open bypass reduced to less than 20% of the total. During 2009, nearly 70% of bariatric procedures done at hospitals in the consortium were laparoscopic bypasses, about a quarter were banding or gastroplasty, and only about 6% of cases involved open bypass.
Concurrent with this shift in type of bariatric surgery performed came a striking drop in in-hospital mortality. In 2002, the rate was 4 deaths/1,000 patients. Over the following 7 years, mortality steadily fell and reached a new low of 0.6 deaths/1,000 patients in 2009, Dr. Smith reported.
"It’s a remarkable achievement – an American surgical success story," commented Dr. John M. Morton, director of bariatric surgery at Stanford (Calif.) University. Dr. Morton attributed the sharp decline in mortality to the rapid switch from open to laparoscopic gastric bypass, the focus starting in 2004 on treating bariatric surgery patients at designated centers of excellence, improved clinical pathways, and better patient selection. "We consistently see mortality rates of 0.1%, 0.3%, tops. That makes bariatric surgery as safe as laparoscopic cholecystectomy and hip replacement," he said in an interview.
Dr. Smith agreed that the rapid drop in the number of open gastric bypass procedures starting in 2005 and their replacement by laparoscopic procedures played a major role in the fall in patient mortality during the mid-2000s.
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The more than 100,000 patients reviewed by Dr. Smith included 17% who were older than 60 years. About 80% were women and about 73% were white. The prevalence of hypertension was 56%, 30% had diabetes, and 22% had hyperlipidemia. Two-thirds of the patients had private medical insurance coverage.
A multivariate analysis identified six factors linked with an increased mortality risk: age older than 60 years, male sex, Medicare coverage, diabetes, open surgery, and gastric bypass surgery. Diabetes had not previously been identified as a mortality risk in published analyses, and the new list did not include hypertension, which had been a risk factor in prior analyses.
On the basis of these factors, Dr. Smith and his associates developed a mortality risk–scoring formula that assigned 1 point for each of four risk factors – male sex, Medicare insurance, open surgery, and gastric bypass – and 0.5 points for each of the other two factors, age 60 years or older and diabetes. After assigning these point values to the patients in the database, they found that patients with a risk score of 3.5 or greater had a sevenfold increased risk of in-hospital mortality, compared with patients with a score of zero or 0.5.
Dr. Smith said he had no disclosures. Dr. Morton said that he has received an educational grant from Ethicon Endo-Surgery, and he has received honoraria from and served on the scientific advisory board of Vibrynt.