Newswise — PHILADELPHIA –Clinical practice guideline recommendations related to screening and treatment can change markedly over time as new evidence about best practices and clinical outcomes of various treatments emerges. In a first-of-its-kind study, Penn Medicine researchers examined high-level recommendations published by the American College of Cardiology (ACC) and the American Heart Association (AHA) between 1998 and 2007 and found that recommendations which were supported by multiple randomized controlled trials were the most “durable” and least likely to change over time. Their work will be published in JAMA.

A Penn research team led by Mark D. Neuman, MD, MSc, assistant professor of Anesthesiology and Critical Care and Senior Fellow in the Leonard David Institute of Health Economics, analyzed changes over time in over 600 Class I ACC/AHA recommendations, each of which recommended strongly in favor of a particular treatment or procedure related to cardiovascular disease.

Based on comparisons of serial editions of ACC/AHA guidelines, the authors observed that 4 out of 5 Class I recommendations remained valid across two guideline editions; however, they also noted that 1 out of every 5 Class I recommendations was either downgraded to a less certain status, reversed so as to recommend against a previously endorsed treatment, or omitted entirely.

Neuman and colleagues also found the odds of a downgrade, reversal, or omission to be more than three times greater among recommendations based on retrospective studies, case reports, or expert opinion versus randomized controlled trials.

While the study was not designed to examine the specific reasons that the individual recommendations were downgraded, supplemental analyses suggested that it was uncommon for recommendations to be downgraded as a result of the emergence of new research studies. Instead, Neuman and colleagues found that many of the downgrades in recommendations that they observed may have come from changes over time in how expert physicians interpreted existing medical research.

“Clinical practice guidelines are used by health care providers to make decisions about treatments for individual patients, and by hospitals, regulators, and insurers to develop quality measures,” says Neuman. "Our study provides new information about the durability of guideline recommendations over time that can help patients, clinicians, administrators, and regulators make better choices about how guideline recommendations can be used to improve patient outcomes.”

Additional Penn authors included J. Sanford Schwartz, MD, University of Pennsylvania Leonard David Institute for Health Economics, division of General Internal Medicine, Perelman School of Medicine and department of Health Care Management, Wharton School of Business; Jennifer N. Goldstein, MD, division of General Internal Medicine, Perelman School of Medicine; and Michael A. Cirullo, BS, department of Anesthesiology and Critical Care.

This work was funded by the National Institute on Aging (KO8AGO43548-02).

# # # Penn Medicine is one of the world's leading academic medical centers, dedicated to the related missions of medical education, biomedical research, and excellence in patient care. Penn Medicine consists of the Raymond and Ruth Perelman School of Medicine at the University of Pennsylvania (founded in 1765 as the nation's first medical school) and the University of Pennsylvania Health System, which together form a $4.3 billion enterprise.The Perelman School of Medicine has been ranked among the top five medical schools in the United States for the past 17 years, according to U.S. News & World Report's survey of research-oriented medical schools. The School is consistently among the nation's top recipients of funding from the National Institutes of Health, with $392 million awarded in the 2013 fiscal year.

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