Data used in calculating the clinical measures for this study are based on the publicly available MedPAR (Medicare Provider Analysis and Review) 1998 and 1997 data sets, which contain information on the approximately 12 million Medicare discharges from the nation’s acute care hospitals annually.

The hospital database contains more than 800 data elements for more than 6,000 U.S. acute care and specialty hospitals. Virtually every general acute care hospital with 25 or more beds in service is included in the database, as well as all hospitals with bonds rated by Standard & Poor’s Corporation. The primary source of these data is the Medicare cost report, which is filed annually by every U.S. hospital that participates in the Medicare program. Data from the Medicare cost report are used in calculating the cost measure for this study.

HCIA-Sachs has used these databases for many years and believes them to be accurate and reliable sources for the types of analyses performed in this study. Medicare patients usually represent about 45 and 50 percent of patients undergoing percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass graft (CABG) surgery, respectively.

THE COMPARISON GROUPS: We assigned each hospital to one of three peer groups according to its teaching and residency program status:

• teaching hospitals with cardiovascular residency programs
• teaching hospitals without cardiovascular residency programs
• non-teaching hospitals

Within each group, we scored hospitals on the basis of their performance on each of the measures relative to other hospitals in their group. First, each hospital was given a single score for each of the eight measures (see list below). These scores were then summed to arrive at a total score for each hospital within each of the three peer groups.

THE PERFORMANCE MEASURES: We compiled a group of eight measures of clinical quality practices and efficiency of operations that we believe constitutes the most reliable, scientific way possible to produce benchmarks for superior hospital performance. We also believe using publicly available data for all hospitals supports this goal.

The measures are:

1. Risk-adjusted medical (acute myocardial infarction) patient mortality index
2. Risk-adjusted surgical patient mortality index (includes PTCA, CABG, and post-operative mortality indices)
3. Risk-adjusted post-operative infection index (post-operative is defined by the presence of a surgical discharge DRG)
4. Risk-adjusted post-operative hemorrhage index (post-operative is defined by the presence of a surgical discharge DRG)
5. Percentage of CABG patients with internal mammary artery use
6. Percentage of PTCA patients with CABG surgeries during the same admission
7. Severity-adjusted average length of stay
8. Wage- and severity-adjusted average cost