American College Of Surgeons - Inspiring Quality: Highest Standards, Better Outcomes

Hospital networks shift volume and adverse surgical events to hubs

OCTOBER 22, 2018
Clinical Congress Daily Highlights, Monday First Edition

An increase in surgical adverse events at hub hospitals after hospital network formation suggests a shift in more complex cases away from non-hub hospitals, according to a study led by Kyle H. Sheetz, MD, MSc, University of Michigan Center for Healthcare Outcomes and Policy, Ann Arbor.

As a result of economic pressure, about 70 percent of the nation’s hospitals are now part of a network, Dr. Sheetz said. The researchers wanted to find out if the quality of surgical care is collectively enhanced across newly formed networks or if “brand erosion” occurs instead, he said.

The researchers conducted a cross-sectional analysis of hospitals joining networks that included locations named to the U.S. News Honor Roll. They studied Medicare patients undergoing colectomy, coronary artery bypass graft (CABG) or hip replacement from 2005 through 2014. The researchers evaluated whether network formation was associated with changes in risk-adjusted rates of serious complications and mortality, per-episode spending and clinical efficiency (spending per day) across hub (primary namesake referral center) and non-hub hospitals.

They found that network formation was associated with a 12–37 percent increase in surgical volume for hub hospitals and a proportionate 15–30 percent decrease in volume for non-hub hospitals for all procedures. For non-hub hospitals, network formation was associated with a decrease in serious complications and mortality following colectomy only. For hub hospitals, network formation was associated with an increase in serious complications and mortality for colectomy and CABG.

“We know that affiliates referred their sick patients to honor roll hospitals,” Dr. Sheetz said. “What we do not know is whether the complications would have happened had the patient stayed at the affiliate.”

Network formation was not associated with a consistent trend towards lower spending or improved efficiency. As a result, hospital network formation may be insufficient to reduce per-episode spending or to improve the clinical efficiency of inpatient surgical care.

View this study’s abstract online here.

Additional Information

The Scientific Forum presentation, Changes in Surgical Quality Associated with Network Formation at America's Highest-Rated Hospitals, was held October 22 at the 2018 Clinical Congress of the American College of Surgeons in Boston. Program, webcast, and audio information is available online at

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