Quality measures improve outcomes more than hospital volume alone

A new study by researchers at the University of California, San Francisco and Baystate Medical Center at Tufts University in Massachusetts concludes that patients facing coronary artery bypass surgery should, as a first priority, select a medical facility that has the highest adherence to quality standards.

The research team sought to determine how volume among individual surgeons, volume differences between hospitals, and differences in quality of care might influence outcomes following coronary artery bypass surgery. According to the researchers, care from high-volume centers or surgeons has been associated with better outcomes post-operatively, but how volume and quality of care were related has not been well understood.

“You could go to the busiest doctor, as many people do,” said study author Andrew Auerbach, MD, MPH, associate clinical professor of medicine at UCSF and director of research for the Division of Hospital Medicine. “But how busy the surgeon is may not matter as much as his or her team’s adherence to quality measures.”

The study, “Shop for Quality or Volume? Volume, Quality, and Outcomes of Coronary Artery Bypass Surgery,” is published in the May 19, 2009 edition of “Annals of Internal Medicine.”

The study examined data on 81,289 patients cared for by 1,451 surgeons at 164 hospitals in the United States participating in Perspective, a voluntary, fee-supported database that measures quality and health care utilization.

“Conventional wisdom suggests that patients in need of surgery should seek care from hospitals and surgeons that perform the procedure often—practice makes perfect,” said study senior author Peter Lindenauer, MD, MSc, director of the Center for Quality of Care Research at Baystate Medical Center and associate professor of medicine at Tufts University School of Medicine.

Very little is known about what makes high volume centers or surgeons more successful, the researchers noted, and the study team sought to investigate whether some of the success factors of high volume centers or surgeons could be replicable at low volume centers. If so, then perhaps some of the risks associated with going to a low volume center could be mitigated, they said.

Findings showed patients have better outcomes when patient care teams strictly follow a routine of individual quality measures, independent of the volume of procedures performed. Those surgeons and hospitals that performed best on meeting every one of six quality measures had the best outcomes, regardless of their patient volume, the researchers found.

The research also showed that meeting quality measures seems to have an “all or nothing” effect. If a patient care team misses individual quality measures, positive post-operative outcomes decline precipitously. Study results suggested a strong association between the number of quality measures missed and death rates regardless of annual hospital volume for coronary artery bypass surgery, with mortality rates similar across all levels of hospital volume if no quality measures are missed.

The six quality measures were whether antimicrobials were used to prevent surgical site infection on the operative day, whether the antimicrobial was appropriate, whether serial compression devices were used to prevent venous thromboembolism on the operative day, and whether aspirin, beta-blockers, or statin lipid-lowering drugs were administered in the first two days after surgery.

The research team found that what made the biggest difference in mortality was whether any of the quality measures were missed. “It doesn’t help if you got your aspirin but you didn’t get your beta-blockers,” said Auerbach. “You have to have everything on the list, or else a good explanation for why you did not.”

Auerbach noted that the researchers assumed doctors in the study were administering medicines smartly; for example, they would not give aspirin to a patient at risk for hemorrhage. “We are saying in essence, it does not matter if you get an ‘A’ in English, and an ‘A’ in science, and an ‘A’ in history, but a ‘B’ in math. You need to have an ‘A’ in everything,” he added.

The study showed that patients cared for at low volume hospitals whose aggregate quality scores were high did as well as patients at high volume centers. “Volume alone did not make as much difference as we thought,” said Auerbach. The implication for payers is that they may want to think in terms of two different domains, volume and quality, to determine the return on their investment in deciding to cover the procedure in one medical center rather than another, according to the research team.

The message for low-volume surgeons is that they can have the same high quality of care with the same level of good outcomes if they have systems in place to ensure that all quality measures are adhered to every single time, said the researchers. Auerbach said that this success depends on the surgeon’s team, that someone on the team is coordinating care to ensure it is reliable and consistent.

“Our results suggest that patients should make use of publicly available quality measures and are likely to benefit from seeking care at hospitals with higher quality scores,” said Lindenauer.

Study co-authors are Joan Hilton, ScD, UCSF Department of Epidemiology and Biostatistics; Judith Maselli, MSPH, UCSF Department of Medicine; and Penelope Pekow, PhD, and Michael Rothberg, MD, MPH, Baystate Medical Center, Center for Quality of Care Research.

The study was funded by a grant from the California HealthCare Foundation.

Baystate Medical Center (BMC), in Springfield, Mass., is an academic, research, and teaching hospital that serves as the western campus of Tufts University School of Medicine.  Serving a population of 800,000, BMC is the region’s only tertiary care referral hospital and Level I Trauma Center, with the only neonatal and pediatric intensive care units, adult cardiac surgery program, and kidney and bone marrow transplantation programs, and consistently ranks among the top 100 hospitals in the country.  For more information, visit www.baystatehealth.org.

UCSF is a leading university dedicated to promoting health worldwide through advanced biomedical and public health research, graduate-level education in the life sciences and health professions, and excellence in patient care. For further information, visit www.ucsf.edu.