Clinical Decisionmaking

Physicians are more likely to use specialty society guidelines that are evidence-based and recently revised

A credible source of a clinical guideline, even a doctor's own specialty society, and familiarity with the guideline do not ensure that physicians will follow it. Physicians are more likely to adhere to guidelines whose recommendations are supported by evidence from randomized clinical trials. Indeed, advances in practice, as in use of coronary angioplasty, may precede changes in guidelines, say Lucian L. Leape, M.D., and Arnold M. Epstein, M.D., M.A., of Harvard Medical School, and their colleagues.

In a study supported by the Agency for Healthcare Research and Quality (HS07098), the researchers found that cardiologists were more likely to follow guidelines developed by the American College of Cardiology/American Heart Association (ACC/AHA) for coronary artery bypass graft surgery (CABG) than angioplasty. The 1990 ACC/AHA CABG guideline was based on a large number of randomized clinical trials. However, the 1988 ACC/AHA guideline on percutaneous coronary angioplasty (PTCA) was based almost entirely on expert opinion.

The researchers used computer programs to classify the appropriateness of PTCA and CABG based on ACC/AHA PTCA (1988 and 1993) and CABG (1990) guidelines and 1990 RAND PTCA and CABG guidelines among randomly sampled Medicare patients who underwent 543 angioplasties and 676 CABGs in five states in 1991 and 1992. Based on the RAND guidelines, 12 percent of PTCA and 9 percent of CABG procedures were classified as inappropriate.

Only 1.5 percent of CABG procedures were inappropriate based on ACC/AHA guidelines. However, based on the 1988 ACC/AHA guidelines, 30 percent of PTCAs were rated inappropriate, whereas 24 percent were rated inappropriate based on the 1993 guidelines. Apparently, practicing cardiologists decided before the 1993 guidelines that an earlier trial of thrombolytic therapy (suggested in the 1988 guidelines) was not needed before trying angioplasty, something the expert panel decided to add to its 1993 guideline. The researchers conclude that to remain useful and credible, guidelines should be revised frequently when practice is advancing rapidly, as in the case of angioplasty.

More details are in "Adherence to practice guidelines: The role of specialty society guidelines," by Dr. Leape, Joel S. Weissman, Ph.D., Eric C. Schneider, M.D., M.Sc., and others, in the January 2003 American Heart Journal 145, pp. 19-26.

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