Do bariatric surgery restrictions improve outcomes?

A Medicare policy limiting where people can undergo weight-loss surgery to so-called “centers of excellence” was not responsible for reducing complications from the procedures, according to a new study.

In 2006, the Centers for Medicare & Medicaid Services (CMS) said it would only pay for bariatric surgery done at hospitals that had certain equipment and medical teams in place and were certified by the American College of Surgeons or the American Society for Metabolic and Bariatric Surgery (ASMBS).

“About a decade ago, there were very real concerns that there were safety problems with bariatric surgery,” said Dr. Justin Dimick, who led the new study at the University of Michigan in Ann Arbor.

At some hospitals, he said, as many as nine percent of patients died during or after surgery.

But that started changing before CMS stepped in with new restrictions, according to Dimick, in part due to less-invasive surgical techniques and better surgeon training.

He and his colleagues used billing codes to track bariatric surgery complications, such as leaks and bleeding, during about 300,000 procedures done between 2004 and 2009 both at centers of excellence and at other hospitals.

They found the proportion of patients on Medicare who had any procedure-related complication dropped from 12 percent before the policy change to eight percent afterward, according to findings published Tuesday in the Journal of the American Medical Association.

Dimick and coauthors report on the complications following bariatric surgery before vs after implementation of a national policy restricting coverage to centers of excellence. In an accompanying Editorial, Greenberg discusses promoting quality surgical care.


Whether the CMS restriction of bariatric surgery to COEs is associated with improved outcomes remains uncertain. Previous studies comparing COEs with non-COEs have largely failed to identify better outcomes at COEs. In contrast, studies examining outcomes before and after the CMS national coverage decision have suggested a beneficial effect of the CMS policy restricting bariatric surgery to COEs.

However, because these latter studies lacked a control group, they were unable to isolate the effect of the CMS national coverage decision from the many other unrelated factors that may have improved bariatric surgery outcomes during the same period. For example, improved outcomes could have been due to the use of lower risk procedures (eg, laparoscopic gastric banding), increasing surgeon experience, fellowships for advanced training in laparoscopic bariatric surgery, or healthier patients undergoing surgery due to broader acceptance of weight loss surgery.

In this study, we sought to evaluate whether the COE component of the national coverage decision was associated with improved bariatric surgery outcomes in Medicare patients. Our objective was to examine outcomes in Medicare patients before compared with after the implementation of the CMS policy that restricted coverage of bariatric surgery to hospitals designated as COEs. We controlled for secular trends using a control group of non-Medicare patients to better account for other factors that may have lead to improved outcomes with time, independent of the CMS policy.


Justin B. Dimick, MD, MPH, Center for Healthcare Outcomes and Policy, 2800 Plymouth Rd, Bldg 520, Office 3144, Ann Arbor, MI 48109 (.(JavaScript must be enabled to view this email address)).

In non-Medicare patients - who had no restrictions on where they received surgery - complication rates also dropped, from between six and seven percent to below five percent.

More complications are to be expected among Medicare patients, the researchers said, due to their age.

“Bariatric surgery got a lot safer over this time period… but it happened in both Medicare and non-Medicare patients,” Dimick told Reuters Health.

“The policy was implemented in 2006, and outcomes were getting better well before that,” he added. “The evidence shows that the policy itself had no benefit.”

Dr. Jaime Ponce, president of ASMBS, disagreed with that assessment and said the new study was limited by its use of billing data instead of more detailed patient records.

Perioperative outcomes of bariatric surgery have improved substantially during the past decade. These improved outcomes might have been attributable to evolving surgical technique and the use of different types of procedures. This included transitioning from open to laparoscopic procedures and the increased use of laparoscopic adjustable gastric banding.

Beyond changes in procedure use, a strong underlying time trend of better outcomes for bariatric surgery in both Medicare and non-Medicare patients was observed. We could not attribute any outcome improvement to the CMS policy restricting performance of bariatric operations on Medicare patients to COEs.

In the first study evaluating the influence of the national coverage decision, Nguyen et al evaluated outcomes before and after the coverage decision in Medicare patients undergoing bariatric surgery at academic health centers. The seemingly better outcomes after the coverage decision were misleading and based on a simple before vs after study design. When secular improvements in outcomes were controlled for in our study, we found no association with the CMS policy and outcomes.

“It’s very difficult to say that accreditation has not helped hospitals or bariatric surgery programs,” said Ponce, who was not involved in the new research.

Previous studies showed the CMS policy was linked to a reduction in procedure costs and in deaths after surgery, he noted.

Ponce said the policy may have encouraged both hospitals that did and didn’t end up being considered centers of excellence to improve their patient care.

“What (the study) showed is that all of the hospitals improved over time,” he told Reuters Health.

According to ASMBS, about 200,000 people have weight loss surgery every year. Surgery is typically recommended for people with a body mass index - a measure of weight in relation to height - of at least 40, or at least 35 if they also have co-occurring health problems such as diabetes or severe sleep apnea.

Dimick and his colleagues are pushing for a move away from the current certification system, toward one that provides more feedback for all hospitals that perform bariatric surgery. Ponce, however, said the Medicare policy is helping patients and should remain in place.

A representative from CMS said the agency is examining its bariatric surgery coverage, including the certification requirement, “and can’t comment on it until we issue a final decision.” That report is expected later this year.

One drawback of the current policy, Dimick said, is that some people on Medicare can’t be treated at nearby hospitals that perform bariatric surgery but aren’t certified.

“The harms here are that Medicare patients who needed surgery might not have been able to have it, because it required travel somewhere else,” he said.

SOURCE: Journal of the American Medical Association, online February 26, 2013


Complications Following Bariatric Procedures

Results  Bariatric surgery outcomes improved during the study period in both Medicare and non-Medicare patients; however, this change was already under way prior to the CMS coverage decision. After accounting for patient factors, changes in procedure type, and preexisting time trends toward improved outcomes, there were no statistically significant improvements in outcomes after (vs before) implementation of the CMS national coverage decision for any complication (8.0% after vs 7.0% before; relative risk [RR], 1.14 [95% CI, 0.95-1.33]), serious complications (3.3% vs 3.6%, respectively; RR, 0.92 [95% CI, 0.62-1.22]), and reoperation (1.0% vs 1.1%; RR, 0.90 [95% CI, 0.64-1.17]). In a direct assessment comparing outcomes at hospitals designated as COEs (n = 179) vs hospitals without the COE designation (n = 519), no significant differences were found for any complication (5.5% vs 6.0%, respectively; RR, 0.98 [95% CI, 0.90-1.06]), serious complications (2.2% vs 2.5%; RR, 0.92 [95% CI, 0.84-1.00]), and reoperation (0.83% vs 0.96%; RR, 1.00 [95% CI, 0.86-1.17]).

Conclusions and Relevance  Among Medicare patients undergoing bariatric surgery, there was no significant difference in the rates of complications and reoperation before vs after the CMS policy of restricting coverage to COEs. Combined with prior studies showing no association of COE designation and outcomes, these results suggest that Medicare should reconsider this policy.

Justin B. Dimick, MD, MPH; Lauren H. Nicholas, PhD; Andrew M. Ryan, PhD; Jyothi R. Thumma, MPH; John D. Birkmeyer, MD

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