Major Finding: Risk-adjusted rates of serious complications in bariatric surgery were 4.0% at designated Centers of Excellence, compared with 2.7% at other hospitals.

Data Source: Study of prospective registry of 7,504 bariatric surgeries in Michigan in 2006–2008.

Disclosures: Dr. Dimick had no relevant disclosures.

SAN ANTONIO — The risk-adjusted rate of serious complications associated with bariatric surgery was paradoxically higher at hospitals designated as a Center of Excellence in Michigan, compared with other centers, a study of more than 7,500 procedures indicates.

“I'm going to cause major controversy,” lead investigator Dr. Justin B. Dimick said at the annual Academic Surgical Congress, where he presented prospective data from the Michigan Bariatric Surgery Collaborative (MBSC) population-based clinical registry.

“The use of bariatric surgery has basically skyrocketed. This operation is not easy … and there is some variability,” said Dr. Dimick of the surgery faculty at the University of Michigan, Ann Arbor.

Dr. Dimick, Nancy Birkmeyer, Ph.D., director of the collaborative, and their colleagues studied all 7,504 patients undergoing laparoscopic or open gastric bypass, sleeve gastrectomy, and other bariatric surgery procedures from 2006 to 2008. Excluded from the study were patients who had had Lap-Band procedures.

They found the lowest risk-adjusted rate of serious complications at a high-volume hospital that was not a designated bariatric Center of Excellence. But even when this institution was removed from the analysis, patients at a designated center did not fare significantly better in terms of reoperation, anastomotic leak, or infectious and medical complication rates, compared with other hospitals.

A total of 5,121 patients (68%) had bariatric surgery at a Center of Excellence. They had a 4.0% risk-adjusted rate of serious complications, compared with 2.7% for the 2,383 patients treated at other hospitals. Outcomes included death or disability, complications, and hospitals readmission. “For all three of these, the Centers of Excellence had worse outcomes,” Dr. Dimick said.

There was no significant difference at 1 year in resolution of comorbidities by institution type, he said. One-year weight loss was not significantly different; patients at designated centers lost an average of 106 pounds versus 100 pounds at other hospitals. Also, improvements from baseline in health-related quality of life did not differ significantly; the Bariatric Quality of Life Index improved 12.4 points in patients at a Center of Excellence versus 11.8 among those treated elsewhere.

Dr. Dimick emphasized that he was not suggesting the Center of Excellence designation is bad. Indeed, he praised professional societies such as the American College of Surgeons and the American Society for Metabolic and Bariatric Surgery for creating standards. Blue Cross and Blue Shield, he added, also designates hospitals as Distinction Centers for Bariatric Surgery using their own criteria. Blue Cross Blue Shield of Michigan funds the MBSC via a pay-for-participation system; hospitals are paid to participate, and bariatric surgeons are required to attend quarterly quality improvement meetings to share best practices.

The lack of significant difference in his study between Centers of Excellence and other facilities could be a result of all hospitals striving to improve because the criteria exist, Dr. Dimick suggested. Still, he added, “Patients seeking bariatric care, at least in Michigan, should not rely only on Centers of Excellence designation.”

The findings may not be generalizable to hospitals outside of Michigan because the surgeons in the study participated in a quality improvement collaboration, a meeting attendee said; Dr. Dimick agreed. In a follow-up video interview, he said, “The story here may be more about the success of quality improvement collaboratives statewide, than the lack of success of the Centers of Excellence program.” In the last two quarters, for example, there were no deaths associated with the approximately 3,000 bariatric procedures performed within that state.

Another meeting attendee pointed out that a study by Dr. Edward H. Livingston and his colleagues at the University of Texas Southwestern Medical Center at Dallas found equivalent outcomes at Centers of Excellence versus other hospitals (Arch. Surg. 2009;144:319-25). These researchers used bariatric surgery data from the 2005 National Inpatient Survey and found no significant differences despite a higher volume of procedures at institutions designated as a Center of Excellence.

“I know Dr. Livingston's study is controversial as well … because he used an administrative database, which has a limited ability to ascertain complications. Our study had the limitation of generalizability beyond Michigan.” Dr. Dimick said.

“The next obvious study is to see if Centers of Excellence have better outcomes outside of this unique quality collaborative,” Dr. Dimick said. “The problem with that is we don't really have population-based data sources outside of the State of Michigan.”

To see a video with Dr. Dimick explaining more about the study, including reactions from colleagues, go to www.youtube.com/ClinicalEndoNews

Bariatric Risks Higher at Centers of Excellence