Patient Care/Clinical Decisionmaking

Strong association found between the use of diagnostic testing and subsequent invasive cardiac procedures

Patients who undergo coronary stress testing (treadmill tests) are more likely to undergo subsequent coronary angiography, and similarly, patients who have angiography are more likely to undergo a revascularization procedure such as angioplasty or coronary artery bypass graft (CABG) surgery. This association between testing and subsequent therapeutic procedures reflects underlying uncertainties about when to test for and treat ischemic heart disease, according to a study supported in part by the Agency for Health Care Policy and Research (HS06813).

David E. Wennberg, M.D., M.P.H., of the Maine Medical Assessment Foundation, and his colleagues analyzed procedure data for all Medicare beneficiaries in northern New England (Maine, New Hampshire, and Vermont) who were treated in 12 coronary angiography service areas in 1992 and 1993. They calculated total stress tests (imaging and nonimaging), coronary angiography, and revascularization procedures. Slightly more than half of the 12,553 Medicare patients who had an imaging stress test subsequently underwent coronary angiography (7,117), and nearly half (3,874) of those who had angiography later underwent coronary revascularization.

These findings suggest that the decision to test is remarkably close to being a decision to treat, according to the researchers. They point out that this cascade of events is more likely to occur when there are differences of opinion about which interventions are appropriate. The researchers conclude that local diagnostic intensity is a critical link to the risk of therapeutic interventions in coronary heart disease.

Details are in "The association between local diagnostic testing intensity and invasive cardiac procedures," by David E. Wennberg, M.D., M.P.H., Merle A. Kellett, M.D., John D. Dickens, Jr., and others, in the April 17, 1996 Journal of the American Medical Association 275(15), pp. 1161-1164.

Physicians vary by specialty in their use of life-sustaining treatments for patients with end-stage disease

Cardiologists are the least likely physicians to withhold or withdraw life sustaining treatment for their patients, and when presented with hypothetical cases, they are more aggressive in their recommendations for such treatment. Oncologists, on the other hand, are more apt to withhold treatment than other physicians and more willing to recommend withholding treatment for the same hypothetical cases.

These differences most likely are due to the lessons the physicians have learned from the practice of their specialties. Cardiologists may view cardiopulmonary resuscitation (CPR) and intensive care favorably because they work well for patients with acute heart disease. On the other hand, cancer patients are unlikely to survive CPR, and oncologists have learned to be conservative in recommending its use, according to researchers at the University of North Carolina at Chapel Hill.

In a study supported in part by the Agency for Health Care Policy and Research (HS06655), they interviewed 158 physicians who cared for hospitalized patients with end-stage congestive heart failure, chronic obstructive pulmonary disease (COPD), cancer, or cirrhosis of the liver to assess the physicians' thresholds for use of specific life-sustaining treatments. The researchers then followed up to determine which decisions were made regarding use or withholding of CPR, ventilator support, or intensive care.

Overall, physicians recommended CPR and ventilator support for patients with end-stage congestive heart failure or COPD if the chance for survival was at least 48 percent, but they required a predicted survival of at least 74 percent for patients with cancer. Cardiologists recommended CPR if the patients with end-stage heart or lung disease had a 30 percent or better likelihood of survival, but other physician groups required a 44 percent to 58 percent probability of success. Oncologists recommended CPR for patients with metastatic cancer if their probability of survival was 82 percent, compared with 58 percent for cardiologists. In practice, cardiologists were least likely to issue orders to withhold treatment and most likely to use life-sustaining treatments for patients with end-stage disease.

The researchers conclude that physicians vary in their willingness to use and in the actual use of life-sustaining treatments, and some of this variation is explained by specialty training. They suggest that efforts to change end-of-life care may be more successful if they include physicians as well as patients and that educational interventions in fellowship programs might help to ensure that all physicians learn similar approaches to end-of-life decisionmaking.

More details are in "Who decides? Physicians' willingness to use life-sustaining treatment," by Laura C. Hanson, M.D., M.P.H., Marion Danis, M.D., Joanne M. Garrett, Ph.D., and Elizabeth Mutran, Ph.D., in the April 8, 1996, Archives of Internal Medicine 156, pp. 785-789.

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