We measured geographic differences in the use of medical and surgical services during 1981 by Medicare beneficiaries (age greater than or equal to 65) in 13 large areas of the United States. The average number of Medicare beneficiaries per site was 340,000. We found large and significant differences in the use of services provided by all medical and surgical specialties. Of 123 procedures studied, 67 showed at least threefold differences between sites with the highest and lowest rates of use. Use rates were not consistently high in one site, but rates for procedures used to diagnose and treat a specific disease varied together, as did alternative treatments for the same condition. These results cannot be explained by the actions of a small number of physicians. We do not know whether physicians in high-use areas performed too many procedures, whether physicians in low-use areas performed too few, or whether neither or both of these explanations are accurate. However, we do know that the differences are too large to ignore and that unless they are understood at a clinical level, uninformed policy decisions that have adverse effects on the health of the elderly may be made.

We convened three panels of physicians to rate the appropriateness of a large number of indications for performing a total of six medical and surgical procedures. The panels followed a modified Delphi process. Panelists separately assigned initial ratings, then met in Santa Monica, California where they received reports showing their initial ratings and the distribution of the other panelists' ratings. They discussed the indications and revised the indications

Carotid endarterectomy is a commonly performed but controversial procedure. We developed from the literature a list of 864 possible reasons for performing carotid endarterectomy, and asked a panel of nationally known experts to rate the appropriateness of each indication using a modified Delphi technique. On the basis of the panel's ratings, we determined the appropriateness of carotid endarterectomy in a random sample of 1302 Medicare patients in three geographic areas who had had the procedure in 1981. Thirty-five percent of the patients in our sample had carotid endarterectomy for appropriate reasons, 32 percent for equivocal reasons, and 32 percent for inappropriate reasons. Of the patients having inappropriate surgery, 48 percent had less than 50 percent stenosis of the carotid artery that was operated on. Fifty-four percent of all the procedures were performed in patients without transient ischemic attacks in the carotid distribution. Of these procedures, 18 percent were judged appropriate, as compared with 55 percent judged appropriate in patients with transient ischemic attacks in the carotid distribution. After carotid endarterectomy, 9.8 percent of patients had a major complication (stroke with residual deficit at the time of hospital discharge or death within 30 days of surgery). We conclude that carotid endarterectomy was substantially overused in the three geographic areas we studied. Furthermore, in situations in which the complication rate is equal to or above the study's aggregate rate, carotid endarterectomy would not be warranted, even in cases with an appropriate indication, because the risks would almost certainly outweigh the benefits.

We studied the appropriateness of use of coronary angiography, carotid endarterectomy, and upper gastrointestinal tract endoscopy and its relationship to geographic variations in the rates of use of these procedures. We selected geographic areas of high, average, and low use of these procedures and randomly sampled Medicare beneficiaries who had received one of the procedures in 1981. We determined the indications for the procedures using a detailed review of medical records and used previously developed ratings of appropriateness to assign an appropriateness score to each case. Differences among sites in levels of appropriateness were small. For example, in the high-use site for coronary angiography, 72% of the procedures were appropriate, compared with 81% in the low-use site. Coronary angiography was performed 2.3 times as frequently in the high-use site compared with the low-use site. Under the conditions of this study, we did find significantly levels of inappropriate use: 17% of cases for coronary angiography, 32% for carotid endarterectomy, and 17% for upper gastrointestinal tract endoscopy. We conclude that differences in appropriateness cannot explain geographic variations in the use of these procedures.