Not Only Expert Panels But Practicing Physicians Should Contribute To Practice Guidelines

Insurance Plans May Make Some Coverage Decisions Based On Incomplete Data

BOSTON--June 19, 1998--A five-state study by Harvard researchers suggests that in certain cases, medical practice guidelines and the treatment recommended by practicing physicians may be two different things.

The researchers say that in other kinds of cases, for which clinical research is more complete, the practicing physicians closely agree with clinical experts, whose beliefs are reflected in most practice guidelines.

The study found that practicing physicians and clinical experts, who may be more familiar with published research, disagree on how to treat the most elderly heart attack patients. Yet experts develop the majority of practice guidelines, which are widely used by insurance plans to determine the treatments that will--and will not--be covered. The researchers say that evaluations of medical practice, part of the basis of practice guidelines, should be founded on the beliefs not only of expert panels but also of practicing physicians. Including the practitioners' perspective would increase the breadth of clinical experience the guidelines represent. The researchers also recommend that more clinical research be done on the most elderly patients--those 75 and older--so medical literature can reflect more complete clinical results.

"This is one of the first large-scale studies on practice patterns to take into account the beliefs of practicing physicians," says lead author John Ayanian, assistant professor of medicine and health care policy at Brigham and Women's Hospital and Harvard Medical School. "It is important for policymakers to understand practicing physicians beliefs if they want to improve care by altering physician behavior and decision-making," Ayanian says.

The study appears in the June 25 New England Journal of Medicine along with a second article and an editorial on quality of care. The second article, co-authored by Lucien Leape of the Harvard School of Public Health, compares the beliefs of different expert panels.

The Medical School researchers presented a mix of cases to 1,058 practicing physicians and a panel of nine clinical experts. The physicians rated the appropriateness of coronary angiography for 20 categories of patients who had recently had a heart attack (acute myocardial infarction). This procedure, x-ray imaging of the coronary arteries after injection of a contrast material, helps in diagnosing the cause of the heart attack and in planning further treatment. The practicing physicians included internists, family practitioners, and cardiologists in California, Florida, New York, Pennsylvania, and Texas. The nine experts also represented a range of specialties.

Though there was general agreement between the practicing physicians and expert panel for most case categories, those in which the patient was 75 or older and had no complications resulted in significant variation between the two groups.

"One potential explanation is that practicing physicians have more experience in seeing positive benefits of angiography for older patients, while the expert panel may be following the medical literature more closely. We don't have an abundant set of data to guide us for older patients," Ayanian says. "We need to improve the evidence available through clinical research to guide us in the care of these patients."

Disagreement also existed within the group of practicing physicians. Their varying expertise and practice environment seemed to influence their beliefs. For complicated cases, cardiologists rated coronary angiography as more appropriate than did primary care physicians. Even among cardiologists, marked variation existed for uncomplicated cases: those who performed invasive procedures gave higher ratings for the appropriateness of angiography than did cardiologists who did not. Furthermore, physicians from hospitals providing invasive treatments like coronary angioplasty--unclogging a plaque-filled artery by inserting a balloon catheter--and bypass surgery rated angiography as more appropriate in uncomplicated cases than did physicians from other hospitals. Physicians working in health maintenance organizations rated angiography as less appropriate than did other physicians.

The decision about whether to perform coronary angiography is a central issue in the care of heart attack patients. The common choice is whether to perform angiography, perhaps leading to angioplasty, or to dissolve blood clots with a thrombolytic medication such as TPA or streptokinase.

The 20 case categories in the study are defined by sets of clinical indications: patient age, time of heart attack, status of thrombolytic therapy, and presence of complications such as chest pain (see attached chart). The physicians rated the appropriateness of coronary angiography for patients in each category using a nine-unit scale with 1 being very inappropriate; 5, uncertain; and 9, very appropriate.

The study, whose senior author is Barbara McNeil, chair of the Department of Health Care Policy at Harvard Medical School, was supported by a grant from the federal Agency for Health Care Policy and Research.

* The ratings were on a 9-unit scale ranging from very inappropriate (1) to uncertain (5) and very appropriate (9).